Add initial workflow for automated vLLM update PRs

.github/workflows/update-dependencies.yml

@@ -0,0 +1,54 @@
+name: Check for dependency updates
+on:
+  schedule:
+    - cron: "0 9 * * *"
+  workflow_dispatch:
+jobs:
+  check_for_update:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+
+      - name: Checkout the config repo
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          fetch-tags: true
+
+      - name: Check for dependency updates
+        shell: bash
+        id: dependency_updates
+        run: |
+          set -xe
+
+          # Install dependency
+          apt update && apt install -y jq yq
+
+          # Tell git who we are for commits
+          git config user.email "${{ github.actor }}"
+          git config user.name "${{ github.actor }}"
+
+          # Get latest vLLM release tag and replace it in various places
+          OLD_VLLM_TAG=$(yq '.api.image.version' chart/values.yml)
+          NEW_VLLM_TAG=$(curl -s https://api.github.com/repos/vllm-project/vllm/releases/latest | jq .tag_name | sed s/\"//g)
+          if [[ $OLD_VLLM_TAG != $NEW_VLLM_TAG ]]; then
+            # Set new release tag output
+            echo new_vllm_tag=$NEW_VLLM_TAG >> $GITHUB_OUTPUT
+            # Update yaml in-place with yq
+            yq e -i '.api.image.version = strenv(NEW_VLLM_TAG)' chart/values.yaml
+            # Can't use in-place editing with jq
+            jq --arg tag $NEW_VLLM_TAG '.properties.api.properties.image.properties.version.default = $tag' chart/values.schema.json.new
+            mv chart/values.schema.json{.new,}
+          fi
+
+      - name: Create Pull Request
+        if: ${{ steps.dependency_updates.outputs.new_vllm_tag }}
+        uses: peter-evans/create-pull-request@v6
+        with:
+          base: main
+          branch: update/vllm-${{ steps.dependency_updates.outputs.new_vllm_tag }}
+          title: "Update dependencies"
+          body: This PR was automatically generated by GitHub Actions.
+          delete-branch: true