Release: Note to switch away from agones-images (#2809)

Since we have few guardrails on accidentally touching `agones-images`
project, adding a note in the release checklist to switch back to a
local development project after running a release.

docs/governance/templates/release_issue.md

@@ -69,6 +69,8 @@ and copy it into a release issue. Fill in relevant values, found inside {}
    `make sdk-publish-csharp RELEASE_VERSION={version}-rc`).
    Will need [NuGet API Key](https://www.nuget.org/account/apikeys) from Agones account.
 - [ ] Run `make do-release`. (if release candidate: `make do-release RELEASE_VERSION={version}-rc`) to create and push the docker images and helm chart.
+- [ ] Run `make shell` and run `gcloud config configurations activate <your development project>` to switch Agones
+    development tooling off of the `agones-images` project.
 - [ ] Do a `helm repo add agones https://agones.dev/chart/stable` / `helm repo update` and verify that the new
  version is available via the command `helm search repo agones --versions --devel`.
 - [ ] Do a `helm install --namespace=agones-system agones agones/agones`