Add Docker Hub credentials to GitHub Actions workflow

Author: tal-haim

.github/workflows/pr.yml

@@ -39,6 +39,9 @@ jobs:
     runs-on: [ self-hosted, Linux ]
     container:
       image: python:3.9.18
+      credentials:
+        username: ${{ secrets.DOCKERHUB_USERNAME }}
+        password: ${{ secrets.DOCKERHUB_TOKEN }}
 
     steps:
       - uses: actions/checkout@v3