run sbt-dependency-submission only on the main branch

Author: ThijsBroersen

.github/workflows/scala.yml

@@ -38,4 +38,5 @@ jobs:
     - name: Run tests
       run: sbt test
     - name: Update Dependency Graph
+      if: github.ref == 'refs/heads/main'
       uses: scalacenter/sbt-dependency-submission@v3