Bump actions/checkout from 4 to 6 (#3831)

* Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v4...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

* Upgrade Python version from 3.9 to 3.12 as 3.9 is no longer supported and a newer version is a requirement for other updates

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Harry <Harry@cadby.co.uk>

.github/workflows/update-generated-schema.yml

@@ -17,7 +17,7 @@ jobs:
         uses: pozetroninc/github-action-get-latest-release@master
         with:
           repository: netbox-community/netbox
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           submodules: true
         if: ${{ steps.netbox-release.outputs.release != vars.SCHEMA_VERSION }}
@@ -25,7 +25,7 @@ jobs:
         uses: actions/setup-python@v5
         id: setup_python
         with:
-          python-version: '3.9'
+          python-version: '3.12'
         if: ${{ steps.netbox-release.outputs.release != vars.SCHEMA_VERSION }}
       - name: cache virtualenv
         uses: actions/cache@v4