Only run sync on tags

Author: MarcusAhlfors

.github/workflows/DiploiBuild.yaml

@@ -13,11 +13,13 @@ env:
   INITIAL_PROJECT_IMAGE_NAME: ${{ github.repository }}-initial-project
   DEMO_TARGET_REPOSITORY: 'https://x-access-token:${{ secrets.DEMO_REPOSITORY_PAT }}@github.com/${{ github.repository }}-demo.git'
   DEMO_TAG_NAME: '${GITHUB_REF#refs/tags/}'
-
+  TAG_NAME: '${GITHUB_REF#refs/tags/}'
+  
 jobs:
 
   DemoSync: 
     runs-on: ubuntu-latest
+    if: startsWith(github.ref, 'refs/tags/v')
     steps:
       - name: Checkout source repository
         uses: actions/checkout@v2