compare latest vcpkg version

.github/workflows/docker-publish.yml

@@ -73,13 +73,30 @@ jobs:
             # keep major version, e.g., v1, tag updated to latest release
             type=semver,pattern=v{{major}},enable=${{startsWith(github.ref, 'refs/tags/v')}}
 
-      - name: Find latest vcpkg release
+      - name: Find latest vcpkg version
         id: find_vcpkg
         uses: gregziegan/fetch-latest-release@v2.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           repo_path: "microsoft/vcpkg"
 
+      - name: Compare latest to current vcpkg version
+        shell: bash
+        run: |
+          set -o pipefail
+          LATEST_VCPKG_VERSION="${{ steps.find_vcpkg.outputs.tag_name }}"
+          CURRENT_VCPKG_VERSION="$(< ./.vcpkg_version)"
+          if [ "$LATEST_VCPKG_VERSION" != "$CURRENT_VCPKG_VERSION" ]; then
+            echo "$LATEST_VCPKG_VERSION" > .vcpkg_version
+            git add .version
+            git diff --staged --exit-code || (
+              git config --global user.name 'github-actions[bot]'
+              git config --global user.email 'github-actions[bot]@users.noreply.github.com'
+              git commit -m "Updated vcpkg version to ${LATEST_VCPKG_VERSION}"
+              git push
+            )
+          fi
+
       # Build and push Docker image with Buildx (don't push on PR)
       # https://github.com/docker/build-push-action
       - name: Build and push Docker image

.vcpkg_version

@@ -0,0 +1 @@
+2023.06.20