Clean up docs dependencies and retain just mkdocs-material

Also fix CI pipeline to deploy docs by supplying correct dependencies.

.github/workflows/ci.yml

@@ -112,19 +112,29 @@ jobs:
     needs: test
     steps:
       - uses: actions/checkout@v4
+
       - name: Configure Git Credentials
         run: |
           git config user.name github-actions[bot]
           git config user.email 41898282+github-actions[bot]@users.noreply.github.com
+
       - uses: actions/setup-python@v5
         with:
           python-version: 3.x
       - run: echo "cache_id=$(date --utc '+%V')" >> $GITHUB_ENV 
+
       - uses: actions/cache@v4
         with:
           key: mkdocs-material-${{ env.cache_id }}
           path: .cache
           restore-keys: |
             mkdocs-material-
-      - run: pip install mkdocs-material 
+
+      - name: Install dependencies
+        run: |
+          curl -sSL https://install.python-poetry.org | python3 -
+          poetry config virtualenvs.create false
+          poetry install --only docs
+        if: steps.cache.outputs.cache-hit != 'true'
+
       - run: mkdocs gh-deploy --force

pyproject.toml

@@ -118,8 +118,6 @@ pytest = ">=7.4.3"
 optional = true
 
 [tool.poetry.group.docs.dependencies]
-sphinx = ">=7.2.6"
-sphinx-tabs = ">=3.4.4"
 mkdocs-material = "^9.5.15"
 mdx-include = "^1.4.2"