fix: renamed secret

Author: mortenzwarenstein

.github/workflows/build-and-publish-image.yml

@@ -32,7 +32,7 @@ jobs:
         if: startsWith(env.image, 'pdok/')
         uses: docker/login-action@v1
         with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1