Use container engine env variable everywhere in the update workflow

We can't build image by docker and push it by podman because they don't share
storage space for images.

.github/workflows/container-autoupdate.yml

@@ -28,7 +28,7 @@ jobs:
             branch: f34-release
     env:
       CI_TAG: '${{ matrix.container-tag }}'
-      # FIXME: Remove this when issue https://github.com/containers/podman/issues/9442 is resolved
+      # FIXME: Switch this to podman when issue https://github.com/containers/podman/issues/9442 is resolved
       CONTAINER_ENGINE: docker
     timeout-minutes: 60
     steps:
@@ -66,13 +66,13 @@ jobs:
             test-logs/coverage-*.log
 
       - name: Login to container registry
-        run: podman login -u ${{ secrets.QUAY_USERNAME }} -p ${{ secrets.QUAY_PASSWORD }} quay.io
+        run: ${CONTAINER_ENGINE} login -u ${{ secrets.QUAY_USERNAME }} -p ${{ secrets.QUAY_PASSWORD }} quay.io
 
-        # we can hardcode the path to the image here because this will be executed only for master image
+      # we can hardcode the path to the image here because this will be executed only for master image
       - name: Add latest tag for master container
         if: ${{ matrix.container-tag == 'master' }}
         run: |
-          podman tag quay.io/rhinstaller/anaconda-${{ matrix.container-type }}:master quay.io/rhinstaller/anaconda-${{ matrix.container-type }}:latest
+          ${CONTAINER_ENGINE} tag quay.io/rhinstaller/anaconda-${{ matrix.container-type }}:master quay.io/rhinstaller/anaconda-${{ matrix.container-type }}:latest
           CI_TAG=latest make -f Makefile.am anaconda-${{ matrix.container-type }}-push
 
       - name: Push container to registry