Add helm chart publishing workflow

.github/workflows/publish-helm.yml

@@ -0,0 +1,35 @@
+name: Publish Helm chart
+
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  release-chart:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Helm
+        uses: azure/setup-helm@v3
+
+      - name: Package chart
+        run: |
+          mkdir -p chart-output
+          helm package charts/xslt-playground -d chart-output
+
+      - name: Generate chart index
+        run: |
+          cd chart-output
+          helm repo index . --url "https://$GITHUB_REPOSITORY_OWNER.github.io/${GITHUB_REPOSITORY#*/}"
+
+      - name: Publish to gh-pages
+        uses: peaceiris/actions-gh-pages@v4
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: chart-output