Make dry-run publish steps' labeling more explicit

From https://github.com/riseproject-dev/python-wheels/pull/204#discussion_r3734442848:

not strictly related to this PR, but what about having a ./.github/workflows/deploy.yml workflow that would contains this to avoid copying it in each individual workflow?

The other benefit is that inside this file we could do something like:

• name: Deploy${{ github.ref != 'refs/heads/main' && ' (dry run)' || '' }}
  uses: ./.github/actions/deploy
  with:
  dry-run: ${{ github.ref != 'refs/heads/main' }}

So the name of the job will actually contain "(dry run)" . Right now, we have the impression that the publish job succeeded and correctly uploaded file on the registry

Further deploy changes probably aren't worth the effort, but taking Julien's suggestion to make the dry-run labeling more explicit would be helpful for our PRs.

.github/workflows/deploy.yml と .github/actions/deploy、および現在 deploy の手順を重複して実行しているワークフローを確認します。dry run が目立つように示されるよう publish ステップのラベル付けを更新し、その後、対象の GitHub Actions workflow を実行して、実際のアップロードが行われなかったことがジョブ名から伝わることを確認します。