adjusted github action for deployment on original repository

Author: lambeolino

.github/workflows/publish-to-gh-pages.yml

@@ -1,6 +1,9 @@
 name: Publish to Github Pages
 run-name: ${{github.actor}} is deploying to Github Pages
-on: [push]
+on:
+  push:
+    branches:
+      - main
 permissions:
   contents: write
 jobs:
@@ -17,3 +20,4 @@ jobs:
         uses: JamesIves/github-pages-deploy-action@v4
         with:
           folder: build
+          repository_name: https://github.com/CodeforLeipzig/leipzigmaps.git