feat: add auto-update versions workflow

The new workflow added in `.github/workflows/auto-update-versions.yml` takes care of automatically updating the Vespa version in the project's documentation. The workflow is triggered either manually or on a daily schedule, and it fetches the latest Vespa version from the Maven repository and updates the relevant files in the repository.

.github/workflows/auto-update-versions.yml

@@ -0,0 +1,71 @@
+name: Auto-update versions
+#
+#  Takes care of updating the Vespa version in the documentation.
+#
+
+on:
+  workflow_dispatch: # Allow manual triggering of the workflow
+
+  schedule:
+    - cron: "0 0 * * *"
+
+  # For testing purposes
+  push:
+    branches: [auto-update-versions]
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  update-vespa-version:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup xq
+        env:
+          URL_PREFIX: "https://github.com/sibprogrammer/xq"
+          INSTALL_DIR: /usr/local/bin/
+          BINARY: xq
+        run: |
+          LATEST_VERSION=$(curl -L -s -H 'Accept: application/json' $URL_PREFIX/releases/latest | sed -e 's/.*"tag_name":"v\([^"]*\)".*/\1/')
+          PLATFORM=$(uname -s | tr A-Z a-z)
+          case "$(uname -m)" in
+            arm64)
+              ARCH=arm64
+              ;;
+            aarch64)
+              ARCH=arm64
+              ;;
+            armv6l)
+              ARCH=armv6
+              ;;
+            armv7l)
+              ARCH=armv7
+              ;;
+            *)
+              ARCH=amd64
+              ;;
+          esac
+          ARCHIVE="${BINARY}_${LATEST_VERSION}_${PLATFORM}_${ARCH}.tar.gz"
+          URL="$URL_PREFIX/releases/download/v${LATEST_VERSION}/$ARCHIVE"
+
+          echo "Installation of $BINARY"
+          rm -f $INSTALL_DIR$BINARY
+          curl -sSL "$URL" | tar xz -C $INSTALL_DIR $BINARY
+          chmod +x $INSTALL_DIR$BINARY
+          echo "Successfully installed at $INSTALL_DIR$BINARY"
+
+      - name: Get Latest Vespa version
+        run: |
+          VESPA_VERSION=$(curl -sSL https://repo1.maven.org/maven2/com/yahoo/vespa/parent/maven-metadata.xml | \
+            grep -oP '<latest>\K([0-9]+\.[0-9]+\.[0-9]+)')
+
+           echo "Vespa version: $VESPA_VERSION"
+
+           VESPA_VERSION=$(curl -sSL https://repo1.maven.org/maven2/com/yahoo/vespa/parent/maven-metadata.xml | \
+            xq -x '/metadata/versioning/latest')
+
+           echo "Vespa version: $VESPA_VERSION"