Bump actions/checkout from 2 to 3

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v3)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/ciff-example-command.yml

@@ -18,7 +18,7 @@ jobs:
           echo ::set-output name=branch::$branch
 
       # Checkout the branch to test
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           repository: ${{ steps.vars.outputs.repository }}
           ref: ${{ steps.vars.outputs.branch }}