Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...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>

.github/workflows/pypi.yml

@@ -8,7 +8,7 @@ jobs:
     publish:
         runs-on: ubuntu-latest
         steps:
-            - uses: actions/checkout@v3
+            - uses: actions/checkout@v4
 
             - name: Set up Python
               uses: actions/setup-python@v4

.github/workflows/pythonpackage.yml

@@ -24,7 +24,7 @@ jobs:
                 version: ["3.7", "3.8", "3.9", "3.10"]
 
         steps:
-            -   uses: actions/checkout@v3
+            -   uses: actions/checkout@v4
 
             -   name: Set up Python ${{ matrix.version }} on ${{ matrix.os }}
                 uses: actions/setup-python@v4
@@ -54,7 +54,7 @@ jobs:
     Linting:
         runs-on: ubuntu-latest
         steps:
-        -   uses: actions/checkout@v3
+        -   uses: actions/checkout@v4
 
         -   name: Set up Python
             uses: actions/setup-python@v4