ci: build gramine-sgx for dev and tagged builds only (#805)

Author: heeckhau

.github/workflows/ci.yml

@@ -216,6 +216,7 @@ jobs:
     needs: build-sgx
     container:
       image: gramineproject/gramine:latest
+    if: github.ref == 'refs/heads/dev' || (startsWith(github.ref, 'refs/tags/v') && contains(github.ref, '.'))
 
     steps:
       - name: Checkout repository