Applied suggestion and edit dependency graph

Signed-off-by: CihatAltiparmak <[email protected]>

Author: CihatAltiparmak

.github/workflows/build_images.yaml

@@ -164,7 +164,7 @@ jobs:
   delete-untagged-images:
     name: Delete Untagged Images
     runs-on: ubuntu-latest
-    needs: nightly_docker
+    needs: [nightly_docker, release_docker]
     permissions:
       contents: read
       packages: write
@@ -176,6 +176,6 @@ jobs:
           owner: 'ros-navigation'
           package-name: 'nav2_docker'
           package-type: 'container'
-          min-versions-to-keep: 5
+          min-versions-to-keep: 20
           delete-only-untagged-versions: 'true'
           token: ${{ secrets.GITHUB_TOKEN }}