Only autorelease the master branch

Author: timmaxw

.github/workflows/main.yml

@@ -58,13 +58,15 @@ jobs:
         mv OpenSCAD2CalculiX-*-x86_64.AppImage OpenSCAD2CalculiX-latest-x86_64.AppImage
 
     - name: Tag latest
+      if: ${{ github.ref == 'refs/heads/master' }}
       uses: richardsimko/update-tag@v1
       with:
         tag_name: latest
       env:
         GITHUB_TOKEN: ${{ github.token }}
 
     - name: Release latest
+      if: ${{ github.ref == 'refs/heads/master' }}
       uses: softprops/action-gh-release@v1
       with:
         tag_name: latest