[CI] Don't try to login/push docker images on forks

Author: lukaszstolarczuk

.github/workflows/reusable_dockers_build.yml

@@ -28,15 +28,16 @@ jobs:
         run: |
           docker build -f .github/docker/${{ matrix.os }}.Dockerfile -t ${{ env.IMG }} .
 
+      # Login and push require login/pass to GHCR - omit these steps on forks
       - name: Login to GitHub Container Registry
-        if: github.event_name != 'pull_request'
+        if: ${{ github.event_name != 'pull_request' && github.repository == 'oneapi-src/unified-memory-framework' }}
         uses: docker/login-action@6d4b68b490aef8836e8fb5e50ee7b3bdfa5894f0 # v3.2.0
         with:
           registry: ghcr.io
           username: bb-ur
           password: ${{ secrets.BB_GHCR_TOKEN }}
 
       - name: Push ${{ matrix.os }} Docker image
-        if: github.event_name != 'pull_request'
+        if: ${{ github.event_name != 'pull_request' && github.repository == 'oneapi-src/unified-memory-framework' }}
         run: |
           docker push ${{ env.IMG }}