Add poetry install (#57)

* Added Python Poetry installation

* Add newline end of action.yml file

* Add comment to describe `Check Poetry Version Input` step

install-python-poetry/README.md

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+# Install Python Poetry
+
+This action will install and setup [python-poetry](https://python-poetry.org/).
+
+Unlike [snok/install-poetry](https://github.com/snok/install-poetry), this action does NOT
+rely on the [poetry installer](https://install.python-poetry.org/).
+
+The poetry installer is recommended for desktop and personal usage, in CI environments, it is best
+to setup poetry from Pypi for maximum control. There have been issues where CI builds failed as 
+`install.python-poetry.org` was down.
+
+```yaml
+- uses: actions/checkout@v4
+- uses: actions/setup-python@v4
+- uses: XanaduAI/cloud-actions/install-python-poetry@main
+- run: poetry --version
+```
+
+## Inputs
+
+### Install a specific version of Poetry
+By default, the latest version of poetry available on Pypi is installed.
+But you can pass a specific version to install, this is recommended in CI as it would
+make the builds more deterministic.
+```yaml
+- uses: XanaduAI/cloud-actions/install-python-poetry@main
+  with:
+    poetry_version: 1.6.2
+```
+
+### Install poetry to a specific directory
+The default installation directory is within `/tmp/`. But you can
+change it using `poetry_home`:
+```yaml
+- uses: XanaduAI/cloud-actions/install-python-poetry@main
+  with:
+    poetry_version: 1.6.2
+    poetry_home: /some/other/directory
+```
+A python venv is created in the directory, and poetry is installed within that venv.
+This ensures that poetry and the calling workflow python packages do not intermix as
+that may lead to poetry attempting to manage it's own dependencies (and can break).
+
+### Adding poetry to PATH
+The default behavior is to add poetry to PATH by creating a symlink.
+This action does NOT update PATH as it can change the python interpreter that
+is being used by the calling workflow. The symlink is created to `/usr/local/bin/poetry`.
+In case you do not want to create the symlink, use the input `add_poetry_to_path` to toggle the behavior.
+If this is set to false, you have to invoke poetry by calling the binary directly.
+```yaml
+- uses: XanaduAI/cloud-actions/install-python-poetry@main
+  id: setup_poetry
+  with:
+    poetry_version: 1.6.2
+    poetry_home: /some/other/directory
+    add_poetry_to_path: false
+
+- run: ${{ steps.setup_poetry.outputs.poetry_bin }} --version
+```
+
+
+## Outputs:
+
+- `poetry_home` -> The directory where poetry is installed
+- `poetry_bin` -> Path to the poetry binary ($POETRY_HOME/bin/poetry)
+
+

install-python-poetry/action.yml

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+name: Install Python Poetry
+description: This action installs and sets up Python Poetry
+
+inputs:
+  poetry_version:
+    type: string
+    description: The version of poetry that will be installed. Omitting this input will install the latest version of poetry.
+    required: false
+    default: ''
+  poetry_home:
+    type: string
+    description: Set a custom directory for POETRY_HOME
+    required: false
+    default: ''
+  add_poetry_to_path:
+    type: boolean
+    description: Update PATH so `poetry` can be invoked directly. Defaults to true
+    required: false
+    default: true
+
+
+outputs:
+  poetry_home:
+    description: 'Path to directory where poetry is installed'
+    value: ${{ steps.poetry.outputs.home }}
+  poetry_bin:
+    description: 'Path to poetry binary'
+    value: ${{ steps.poetry.outputs.bin }}
+
+
+runs:
+  using: composite
+  steps:
+    - name: Check Python available
+      shell: bash
+      run: |
+        if ! command -v python &> /dev/null
+        then
+          echo "::error title=Missing Python::Could not find a python installation. Make sure to use actions/setup-python prior to calling this action."
+          exit 1
+        fi
+
+    # This step outputs `==<inputs.poetry_version>` only if a version is specified by the calling workflow.
+    # This is done so that if the calling workflow omits version, then the `Install Poetry` step renders to `pip install poetry`
+    # And if a version is specified, then that step would instead render to `pip install poetry==<inputs.poetry_version>`
+    - name: Check Poetry Version Input
+      shell: bash
+      id: poetry_version
+      if: inputs.poetry_version != ''
+      env:
+        INPUT_POETRY_VERSION: ${{ inputs.poetry_version }}
+      run: echo "version===$INPUT_POETRY_VERSION" >> $GITHUB_OUTPUT
+
+    - name: Setup POETRY_HOME
+      shell: bash
+      id: poetry_home
+      env:
+        INPUT_POETRY_HOME: ${{ inputs.poetry_home }}
+      run: |
+        if [ "$INPUT_POETRY_HOME" == "" ]; then
+          poetry_home=$(mktemp -d)
+        else
+          poetry_home=$INPUT_POETRY_HOME
+        fi
+        echo "poetry_home=$poetry_home" >> $GITHUB_OUTPUT
+
+
+    - name: Install Poetry
+      id: poetry
+      shell: bash
+      env:
+        POETRY_HOME: ${{ steps.poetry_home.outputs.poetry_home }}
+      run: |
+        python3 -m venv $POETRY_HOME
+        $POETRY_HOME/bin/python -m pip install poetry${{ steps.poetry_version.outputs.version }}
+        
+        echo "home=$POETRY_HOME" >> $GITHUB_OUTPUT
+        echo "bin=$POETRY_HOME/bin/poetry" >> $GITHUB_OUTPUT
+
+    - name: Validate Poetry Installation
+      shell: bash
+      run: ${{ steps.poetry.outputs.home }}/bin/poetry --version
+
+    # This step symlinks the poetry binary to /usr/local/bin/poetry
+    # The reason for doing this instead of pre-pending the directory to GITHUB_PATH is so that
+    # the python binary being used by the calling workflow is not altered.
+    # If this step did `echo '/path/to/poetry/bin' >> GITHUB_PATH` .. that /bin would also contain a python
+    # binary, and if the calling workflow used python commands after installing poetry, they may use the wrong
+    # python binary without knowing it.
+    # This avoids that situation by not updating PATH.
+    - name: Add to PATH
+      if: inputs.add_poetry_to_path == 'true'
+      shell: bash
+      run: |
+        ln -sf ${{ steps.poetry.outputs.home }}/bin/poetry /usr/local/bin/poetry