Bump mrkkrp/ormolu-action from 14 to 15

Bumps [mrkkrp/ormolu-action](https://github.com/mrkkrp/ormolu-action) from 14 to 15.
- [Release notes](https://github.com/mrkkrp/ormolu-action/releases)
- [Changelog](https://github.com/haskell-actions/run-ormolu/blob/master/CHANGELOG.md)
- [Commits](haskell-actions/run-ormolu@v14...v15)

---
updated-dependencies:
- dependency-name: mrkkrp/ormolu-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/pipeline.yml

@@ -21,7 +21,7 @@ jobs:
           ghc-version: "9.2"
 
       - name: Formatting
-        uses: mrkkrp/ormolu-action@v14
+        uses: mrkkrp/ormolu-action@v15
 
       - name: Set up HLint
         uses: haskell/actions/hlint-setup@v2