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/python_actions.yml

@@ -31,9 +31,9 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: Checkout SupportScripts
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: SpiNNakerManchester/SupportScripts
         path: support
@@ -79,9 +79,9 @@ jobs:
       with:
         python-version: ${{ matrix.python-version }}
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: Checkout SupportScripts
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: SpiNNakerManchester/SupportScripts
         path: support