feat(ci): chart release workflow

Signed-off-by: Thuan Vo <thvo@redhat.com>

.github/workflows/helm-release.yml

@@ -0,0 +1,48 @@
+name: Release Helm Chart
+
+on:
+  release:
+    types:
+      - "published"
+
+defaults:
+  run:
+    shell: bash
+
+env:
+  REPOSITORY: ${{ github.repository_owner }}/cryostatio.github.io
+  REF: main
+  CHART_VERSION: ${{ github.release.tag_name }}
+  CHART_DOWNLOAD_URL: ${{ github.release.assets[0].browser_download_url }}
+
+jobs:
+  helm-release:
+    runs-on: ubuntu-latest
+    if: ${{ github.repository_owner == 'cryostatio' }}
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          repository: ${{ env.REPOSITORY }}
+          ref: ${{ env.REF }}
+          token: "${{ secrets.CHART_REPO_TOKEN }}"
+      - name: Generate chart index
+        run: |
+          DEST="${PWD}/helm-charts"
+          TMP_DIR="$(mktemp -d)"
+          cleanup() {
+              rm -rf "${TMP_DIR}"
+          }
+          trap EXIT cleanup
+          pushd ${TMP_DIR}
+          curl -LO $CHART_DOWNLOAD_URL && helm repo index . --url ${CHART_DOWNLOAD_URL%/*} --merge ${DEST}/index.yaml
+          mv index.yaml ${DEST}/index.yaml
+          popd
+      - name: Configure Git
+        run: |
+          git config user.name "$GITHUB_ACTOR"
+          git config user.email "$GITHUB_ACTOR@users.noreply.github.com"
+      - name: Commit and push chart index
+        run: |
+          git add --all
+          git commit -m "build(helm-charts): release chart version $CHART_VERSION"
+          git push

charts/cryostat/README.md

@@ -1,6 +1,33 @@
 # Cryostat Helm Chart
 A Helm chart for deploying [Cryostat](https://cryostat.io/) on Kubernetes and OpenShift
 
+## Usage
+
+[Helm](https://helm.sh) must be installed to use the charts.  Please refer to
+Helm's [documentation](https://helm.sh/docs) to get started.
+
+Once Helm has been set up correctly, add the repo as follows:
+
+```bash
+helm repo add cryostat https://cryostat.io/helm-charts
+```
+
+If you had already added this repo earlier, run `helm repo update` to retrieve
+the latest versions of the packages.  You can then run `helm search repo
+cryostat` to see the charts.
+
+To install the `cryostat` chart:
+
+```bash
+helm install cryostat-sample cryostat/cryostat
+```
+
+To uninstall the chart:
+
+```bash
+helm uninstall cryostat-sample
+```
+
 ## Parameters
 
 ### Cryostat Container