Remove not needed GH_USERNAME and update some comments

Author: stronk7

.github/workflows/test_buildx_and_publish.yml

@@ -80,7 +80,7 @@ jobs:
         uses: docker/login-action@v2
         with:
           registry: ghcr.io
-          username: ${{ secrets.GH_USERNAME }}
+          username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       # https://github.com/docker/build-push-action#multi-platform-image
@@ -94,10 +94,6 @@ jobs:
           tags: ${{ steps.calculatetags.outputs.tags }}
 
       # https://github.com/peter-evans/dockerhub-description
-      # It's horrible that we need to use password here instead of PAT, because
-      # that's only available via CLI what defeats 2FA. Anyway, we need to
-      # auto-update the description, so using it (till available via PAT).
-      # Link: https://github.com/peter-evans/dockerhub-description/issues/10
       # Note that we only update the description with the master branch version.
       - name: Set Docker Hub description from README.md
         if: github.ref == 'refs/heads/master'