chore(deps): 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] <[email protected]>

Author: dependabot[bot]

.github/workflows/buildtest.yml

@@ -50,7 +50,7 @@ jobs:
           brew upgrade
           brew install lua
       - name: Setup Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version-file: '.python-version'
       - name: Setup venv
@@ -189,7 +189,7 @@ jobs:
           [System.IO.Compression.ZipFile]::ExtractToDirectory($zip, $lua)
           Write-Output "$($lua)" | Out-File -FilePath $env:GITHUB_PATH -Encoding utf8 -Append
       - name: Setup Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version-file: '.python-version'
       - name: Setup venv