Bump actions/setup-python from 5 to 6

Bumps [actions/setup-python](https://github.com/actions/setup-python) from 5 to 6.
- [Release notes](https://github.com/actions/setup-python/releases)
- [Commits](actions/setup-python@v5...v6)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Eivind Jahren <ejah@equinor.com>

Author: dependabot[bot]

.github/workflows/style.yml

@@ -13,7 +13,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - name: Setup Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: 3.12
       - name: Install dependencies

.github/workflows/testing.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v6
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: "${{ matrix.python-version }}"
       - name: Install Ubuntu Packages