ReviewApps: CI pin external-dns to 2.x version

Pin the version of deployed external-dns to `2.y.z`, using SemVer
matching. (`^2.2.1`)

Update the properties for the service account keys per
*Upgrading to 2.0.0* of the `stable/external-dns` README.

Add `aws.batchChangeSize=400` to combat messages about RDATA being
too large.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/64356

scripts/review_apps/review-apps.sh

@@ -132,13 +132,14 @@ function install_external_dns() {
     echoinfo "Installing external-dns Helm chart"
     helm repo update
     # Default requested: CPU => 0, memory => 0
-    helm install stable/external-dns \
+    helm install stable/external-dns --version '^2.2.1' \
       -n "${release_name}" \
       --namespace "${KUBE_NAMESPACE}" \
       --set provider="aws" \
-      --set aws.secretKey="${REVIEW_APPS_AWS_SECRET_KEY}" \
-      --set aws.accessKey="${REVIEW_APPS_AWS_ACCESS_KEY}" \
+      --set aws.credentials.secretKey="${REVIEW_APPS_AWS_SECRET_KEY}" \
+      --set aws.credentials.accessKey="${REVIEW_APPS_AWS_ACCESS_KEY}" \
       --set aws.zoneType="public" \
+      --set aws.batchChangeSize=400 \
       --set domainFilters[0]="${domain}" \
       --set txtOwnerId="${KUBE_NAMESPACE}" \
       --set rbac.create="true" \