CI: Avoid global git settings in automerge action

Author: florian-wagner

.github/workflows/main.yml

@@ -69,8 +69,8 @@ jobs:
       - name: Merge dev -> master
         working-directory: source
         run: |   
-          git config --global user.name 'Florian Wagner'
-          git config --global user.email 'florian-wagner@users.noreply.github.com'
+          git config user.name 'Florian Wagner'
+          git config user.email 'florian-wagner@users.noreply.github.com'
           git checkout master
           git merge dev --no-commit
           git push origin master