resolving the issue #14 Change GHA Runner image name

Signed-off-by: Ryder-07 <[email protected]>

Author: Ryder-07

.github/workflows/publish-image.yml

@@ -19,7 +19,7 @@ env:
   # Use docker.io for Docker Hub if empty
   REGISTRY: ghcr.io
   # github.repository as <account>/<repo>
-  IMAGE_NAME: ${{ github.repository }}
+  IMAGE_NAME: cncf/external-gha-runner
   # Map current release tag to the version of booty
   BOOTY_VERSION: $GITHUB_REF_NAME
   # Map last repo update to the build timestamp