Add docs links to helm NOTES.txt (#4953)

* add docs links to helm NOTES.txt

Author: oseoin

charts/nginx-ingress/README.md

@@ -48,6 +48,14 @@ To upgrade the CRDs, pull the chart sources as described in [Pulling the Chart](
 kubectl apply -f crds/
 ```
 
+Alternatively, CRDs can be upgraded without pulling the chart by running:
+
+```console
+kubectl apply -f https://raw.githubusercontent.com/nginxinc/kubernetes-ingress/v3.4.2/deploy/crds.yaml
+```
+
+In the above command, `v3.4.2` represents the version of NGINX Ingress Controller release rather than the Helm chart version.
+
 > **Note**
 >
 > The following warning is expected and can be ignored: `Warning: kubectl apply should be used on resource created by

charts/nginx-ingress/templates/NOTES.txt

@@ -1 +1,13 @@
-The NGINX Ingress Controller has been installed.
+NGINX Ingress Controller {{ .Chart.AppVersion }} has been installed.
+
+For release notes for this version please see: https://docs.nginx.com/nginx-ingress-controller/releases/
+
+Installation and upgrade instructions: https://docs.nginx.com/nginx-ingress-controller/installation/installing-nic/installation-with-helm/
+
+{{ if .Release.IsUpgrade -}}
+If you are upgrading from a version of the chart that uses older Custom Resource Definitions (CRD) it is necessary to manually upgrade the CRDs as this is not managed by Helm.
+To update to the latest version of the CRDs:
+  $ kubectl apply -f https://raw.githubusercontent.com/nginxinc/kubernetes-ingress/v{{ .Chart.AppVersion }}/deploy/crds.yaml
+
+More details on upgrading the CRDs: https://docs.nginx.com/nginx-ingress-controller/installation/installing-nic/installation-with-helm/#upgrading-the-crds
+{{- end -}}

docs/content/installation/installing-nic/installation-with-helm.md

@@ -42,6 +42,14 @@ To upgrade the CRDs, pull the chart sources as described in [Pulling the Chart](
 kubectl apply -f crds/
 ```
 
+Alternatively, CRDs can be upgraded without pulling the chart by running:
+
+```console
+kubectl apply -f https://raw.githubusercontent.com/nginxinc/kubernetes-ingress/v3.4.2/deploy/crds.yaml
+```
+
+In the above command, `v3.4.2` represents the version of NGINX Ingress Controller release rather than the Helm chart version.
+
 {{<note>}}The following warning is expected and can be ignored: `Warning: kubectl apply should be used on resource created by either kubectl create --save-config or kubectl apply`.
 
 Make sure to check the [release notes](https://www.github.com/nginxinc/kubernetes-ingress/releases) for a new release for any special upgrade procedures.