👷(helm) add a github workflow to publish a chart

We have a dedicated deployment repository, also containing
the Helm chart. To avoid duplicating and maintaining twice
a chart, we decided to publish our Helm chart.

At first we tried the official chart releaser action, however,
this ended in creating a new release on Github for each chart
update, which wasn't acceptable.

.github/workflows/release-helm-chart.yaml

@@ -0,0 +1,35 @@
+name: Release Chart
+run-name: Release Chart
+
+on:
+  push:
+    paths:
+      - src/helm/meet/**
+
+jobs:
+  release:
+    # depending on default permission settings for your org (contents being read-only or read-write for workloads), you will have to add permissions
+    # see: https://docs.github.com/en/actions/security-guides/automatic-token-authentication#modifying-the-permissions-for-the-github_token
+    permissions:
+      contents: write
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Cleanup
+        run: rm -rf ./src/helm/extra
+
+      - name: Install Helm
+        uses: azure/setup-helm@v4
+        env:
+          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+
+      - name: Publish Helm charts
+        uses: numerique-gouv/helm-gh-pages@add-overwrite-option
+        with:
+          charts_dir: ./src/helm
+          linting: off
+          token: ${{ secrets.GITHUB_TOKEN }}