Update release.yml

Author: lzchen

.github/workflows/release.yml

@@ -56,6 +56,7 @@ jobs:
             # not making a patch release
             if ! grep --quiet "^## Version ${STABLE_VERSION}/${UNSTABLE_VERSION} " CHANGELOG.md; then
               echo the pull request generated by prepare-release-branch.yml needs to be merged first
+              echo ${STABLE_VERSION}/${UNSTABLE_VERSION}
               exit 1
             fi
           fi