Fix workflow: image tag

Author: mlookaxw

.github/workflows/maven-publish.yml

@@ -70,4 +70,4 @@ jobs:
         with:
               context: .
               push: true
-              tags: ghcr.io/$GITHUB_REPOSITORY_OWNER/yamles-utils:${{ needs.build.outputs.PROJECT_VERSION }}
+              tags: ghcr.io/${{ github.repository_owner }}/yamles-utils:${{ needs.build.outputs.PROJECT_VERSION }}