Use repository variables for non-sensitive fields (#1427)

Author: 0x2b3bfa0

.github/workflows/images.yml

@@ -90,7 +90,7 @@ jobs:
       - uses: docker/login-action@v2
         with:
           registry: docker.io
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          username: ${{ vars.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_PASSWORD }}
       - uses: docker/login-action@v2
         with: