reintroduce helm-docs step in ci (#8164)

.github/workflows/ci.yaml

@@ -137,6 +137,17 @@ jobs:
         run: |
           ./build/run-in-docker.sh ./hack/verify-chart-lint.sh
 
+      - name: Run helm-docs
+        run: |
+          GOBIN=$PWD GO111MODULE=on go install github.com/norwoodj/helm-docs/cmd/helm-docs@v1.6.0
+          ./helm-docs --chart-search-root=${GITHUB_WORKSPACE}/charts
+          DIFF=$(git diff ${GITHUB_WORKSPACE}/charts/ingress-nginx/README.md)
+          if [ ! -z "$DIFF" ]; then
+            echo "Please use helm-docs in your clone, of your fork, of the project, and commit a updated README.md for the chart. https://github.com/kubernetes/ingress-nginx/blob/main/RELEASE.md#d-edit-the-valuesyaml-and-run-helm-docs"
+          fi
+          git diff --exit-code
+          rm -f ./helm-docs
+
       - name: fix permissions
         run: |
           sudo mkdir -p $HOME/.kube