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] <support@github.com>

Author: dependabot[bot]

.github/workflows/mypy.yaml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-20.04
     steps:
       # Checkout the code
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: jpetrucciani/mypy-check@master
         with:
           requirements: 1.6.0

.github/workflows/release.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Create release archive and notes
         run: .github/workflows/create_archive_and_notes.sh
       - name: Publish wheel dist