build(deps): bump actions/checkout from 2 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v4)

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

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

Author: dependabot[bot]

.github/workflows/publish-to-pypi.yml

@@ -14,7 +14,7 @@ jobs:
     if: github.repository == 'django-components/djc-ext-pydantic'
     steps:
       - name: Checkout the repo
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Setup python
         uses: actions/setup-python@v5