docs(ci): improve release note template (#5791)

* docs(ci): improve release note template

* improve reference

* Update scripts/releaser.sh

Author: mloiseleur

docs/release.md

@@ -41,9 +41,9 @@ You must be an official maintainer of the project to be able to do a release.
 - Run `scripts/releaser.sh` to create a new GitHub release. Alternatively you can create a release in the GitHub UI making sure to click on the autogenerate release node feature.
 - The step above will trigger the Kubernetes based CI/CD system [Prow](https://prow.k8s.io/?repo=kubernetes-sigs%2Fexternal-dns). Verify that a new image was built and uploaded to `gcr.io/k8s-staging-external-dns/external-dns`.
 - Create a PR in the [k8s.io repo](https://github.com/kubernetes/k8s.io) by taking the current staging image using the sha256 digest. They can be obtained with `scripts/get-sha256.sh`. Once the PR is merged, the image will be live with the corresponding tag specified in the PR.
-  - See https://github.com/kubernetes/k8s.io/pull/540 for reference
+  - See https://github.com/kubernetes/k8s.io/pull/8466 for reference
 - Verify that the image is pullable with the given tag
-  - `docker run registry.k8s.io/external-dns/external-dns:v0.16.0 --version`
+  - `docker run registry.k8s.io/external-dns/external-dns:v0.x.0 --version`
 - Branch out from the default branch and run `scripts/version-updater.sh` to update the image tag used in the kustomization.yaml and in documentation.
 - Create the PR with this version change.
 - Create an issue to release the corresponding Helm chart via the chart release process (below) assigned to a chart maintainer

scripts/releaser.sh

@@ -30,6 +30,15 @@ function generate_changelog {
   echo "## :package: Others"
   echo
   cat "${MERGED_PRS}" | grep -v "\!" | grep -v feat[:\(] | grep -v fix[:\(] | grep -v docs[:\(]
+
+  echo
+  echo "## :package: Docker Image"
+  echo
+  echo "\`\`\`sh"
+  echo "# This pull command only works when it's released
+  echo "docker pull registry.k8s.io/external-dns/external-dns:${VERSION}"
+  echo "\`\`\`"
+
 }
 
 function create_release {
@@ -66,12 +75,14 @@ gh pr list \
   " | sort > "${MERGED_PRS}"
 
 if [ $# -ne 1 ]; then
+  export VERSION="v0.x.0"
   generate_changelog "${MERGED_PRS}"
   echo "** DRY RUN **"
   echo
-  echo "To create a release: ./releaser.sh v0.17.0"
+  echo "To create a release: ./releaser.sh v0.x.0"
 else
-  generate_changelog "${MERGED_PRS}" | gh release create "$1" -t "$1" -p -F -
+  export VERSION="$1"
+  generate_changelog "${MERGED_PRS}" | gh release create "${VERSION}" -t "${VERSION}" -p -F -
 fi
 
 rm -f "${MERGED_PRS}"