Update to new helm stable repo (#12137)

Switch out deprecated helm repo for new stable repo.

- https://www.cncf.io/blog/2020/11/05/helm-chart-repository-deprecation-update/
- https://helm.sh/docs/faq/#i-am-getting-a-warning-about-unable-to-get-an-update-from-the-stable-chart-repository

(cherry picked from commit 128c991)
(cherry picked from commit 868ff46)

chart/README.md

@@ -37,7 +37,7 @@ cluster using the [Helm](https://helm.sh) package manager.
 To install this repository from source (using helm 3)
 ```bash
 kubectl create namespace airflow
-helm repo add stable https://kubernetes-charts.storage.googleapis.com
+helm repo add stable https://charts.helm.sh/stable/
 helm dep update
 helm install airflow . --namespace airflow
 ```

chart/requirements.lock

@@ -1,6 +1,6 @@
 dependencies:
 - name: postgresql
-  repository: https://kubernetes-charts.storage.googleapis.com
+  repository: https://charts.helm.sh/stable/
   version: 6.3.12
 digest: sha256:58d88cf56e78b2380091e9e16cc6ccf58b88b3abe4a1886dd47cd9faef5309af
 generated: "2020-06-21T19:11:53.498134738+02:00"

scripts/ci/kubernetes/ci_run_helm_testing.sh

@@ -25,4 +25,4 @@ echo "Chart directory is $CHART_DIR"
 docker run -w /airflow-chart -v "$CHART_DIR":/airflow-chart \
   --entrypoint /bin/sh \
   aneeshkj/helm-unittest \
-  -c "helm repo add stable https://kubernetes-charts.storage.googleapis.com; helm dependency update ; helm unittest ."
+  -c "helm repo add stable https://charts.helm.sh/stable/; helm dependency update ; helm unittest ."

scripts/ci/libraries/_kind.sh

@@ -296,7 +296,7 @@ function deploy_airflow_with_helm() {
     verbose_kubectl create namespace "${HELM_AIRFLOW_NAMESPACE}"
     verbose_kubectl create namespace "test-namespace"
     pushd "${AIRFLOW_SOURCES}/chart" || exit 1
-    verbose_helm repo add stable https://kubernetes-charts.storage.googleapis.com
+    verbose_helm repo add stable https://charts.helm.sh/stable/
     verbose_helm dep update
     verbose_helm install airflow . --namespace "${HELM_AIRFLOW_NAMESPACE}" \
         --set "defaultAirflowRepository=${DOCKERHUB_USER}/${DOCKERHUB_REPO}" \