ci(github): fix checklist comment (#11666)

xrel: #11654

Signed-off-by: Charly Molter <charly.molter@konghq.com>

.github/workflows/check.yaml

@@ -61,4 +61,4 @@ jobs:
             - [ ] Does it need to be backported according to the [backporting policy](../blob/master/CONTRIBUTING.md#backporting)? ([this](https://github.com/kumahq/kuma/actions/workflows/auto-backport.yaml) GH action will add "backport" label based on these [file globs](https://github.com/kumahq/kuma/blob/master/.github/workflows/auto-backport.yaml#L6), if you want to prevent it from adding the "backport" label use [no-backport-autolabel](https://github.com/kumahq/kuma/blob/master/.github/workflows/auto-backport.yaml#L8) label)
             [1]: https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword
 
-        run: gh pr comment -R "${{ github.repository }}" "${{ github.event.pull_request.number }}" -b ${{ env.CHECKLIST_MESSAGE}}
+        run: echo '${{ env.CHECKLIST_MESSAGE }}' | gh pr comment -R "${{ github.repository }}" "${{ github.event.pull_request.number }}" -F -