Bump actions/checkout from 1 to 3

Bumps [actions/checkout](https://github.com/actions/checkout) from 1 to 3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v1...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/pr_checks.yml

@@ -18,7 +18,7 @@ jobs:
     if: github.event_name == 'pull_request'
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v3
 
     - name: Check that CHANGELOG has been updated
       run: |