[CI] block HW-related workflow on forks

Author: lukaszstolarczuk

.github/workflows/gpu.yml

@@ -12,6 +12,7 @@ jobs:
   # TODO: add support for Windows
   ubuntu-build:
     name: Build - Ubuntu
+    if: github.repository == 'oneapi-src/unified-memory-framework' # run only on upstream; forks will not have the HW
 
     strategy:
       matrix: