Add check_changes in diskgalaxy workflow (#1558)

### Description
DiskGalaxy workflow is preventing a trivial PR from passing all tests
immediately. This PR fixes it.

### Checklist
_Before this pull request can be reviewed, all of these tasks should be
completed. Denote completed tasks with an `x` inside the square brackets
`[ ]` in the Markdown source below:_
- [ ] I have added a description (see above).
- [ ] I have added a link to any related issues (if applicable; see
above).
- [ ] I have read the [Contributing
Guide](https://github.com/quokka-astro/quokka/blob/development/CONTRIBUTING.md).
- [ ] I have added tests for any new physics that this PR adds to the
code.
- [ ] *(For quokka-astro org members)* I have manually triggered the GPU
tests with the magic comment `/azp run`.

Author: chongchonghe

.github/workflows/rocm-diskgalaxy-container.yml

@@ -23,8 +23,15 @@ env:
   IS_INTERNAL_PR: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository }}
 
 jobs:
+  check_changes:
+    uses: ./.github/workflows/check_changes.yml
+    with:
+      workflow_file: '.github/workflows/rocm-diskgalaxy-container.yml'
+
   build-and-push:
     runs-on: ubuntu-latest
+    needs: check_changes
+    if: needs.check_changes.outputs.has_non_docs_changes == 'true'
 
     steps:
       - name: Checkout