chore: add extra details to image naming convention

Addresses #8908 (comment)

.github/workflows/sub-deploy-integration-tests-gcp.yml

@@ -654,6 +654,7 @@ jobs:
       # (This is unlikely, because each image created by a workflow has a different name.)
       #
       # The image name must also be 63 characters or less.
+      # More info: https://cloud.google.com/compute/docs/naming-resources#resource-name-format
       #
       # Force the image creation (--force) as the disk is still attached even though is not being
       # used by the container.

.github/workflows/sub-find-cached-disks.yml

@@ -81,6 +81,8 @@ jobs:
       #
       # Disk image names in GCP are limited to 63 characters, so we need to limit
       # branch names to 12 characters.
+      # Check the `create-state-image` in `sub-deploy-integration-tests-gcp.yml` for more details in image names.
+      # More info: https://cloud.google.com/compute/docs/naming-resources#resource-name-format
       #
       # Passes ${{ inputs.network }} to subsequent steps using $NETWORK env variable.
       # Passes ${{ env.GITHUB_REF_SLUG_URL }} to subsequent steps using $SHORT_GITHUB_REF env variable.