Add helm-docs reference updates for chart's README (#1836)

docs/release_guide.md

@@ -55,6 +55,17 @@ and build and push Docker images for OSM and the demo to the
 In the description section of the new release, add information about feature additions, bug fixes,
 and any other administrative tasks completed on the repository.
 
+## Update README chart with helm-docs
+
+Chart's README is autogenerated with [helm-docs](https://github.com/norwoodj/helm-docs). Once versioning has been addressed
+under `charts/osm/Chart.yaml`, you can, for example, update the README using `helm-docs` as follows:
+
+```
+go get github.com/norwoodj/helm-docs/cmd/helm-docs # This will add helm-docs on modules if you have GO111MODULE enabled
+cd charts/osm
+helm-docs                                          # Assuming $GOBIN is available on $PATH
+```
+
 ## Create a Helm chart release
 
 * create a Git tag from main in the format `chart/x.x.x` where `x.x.x` is the chart version