ci(semantic-release): notify JuliaRegistrator only upon new releases

If the release process successfully ran but did not result in a new
release getting published, JuliaRegistrator should not be notified. This
was a situation that was unlikely to happen in this repository due to
its feature branch/development/main workflow, but it would have
triggered incorrectly otherwise.

.github/workflows/Release.yml

@@ -15,6 +15,7 @@ jobs:
         uses: actions/checkout@v4
       - name: Semantic Release
         uses: cycjimmy/semantic-release-action@v4
+        id: semantic-release
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
@@ -25,5 +26,6 @@ jobs:
             @ethima/semantic-release-configuration
       - name: Notify JuliaRegistrator of new release
         uses: peter-evans/commit-comment@v3
+        if: steps.semantic-release.outputs.new_release_published == 'true'
         with:
           body: '@JuliaRegistrator register branch=main'