GH Actions: bump to Ruff 0.15.x (was 0.14.x)

See the blog post about the release of Ruff v0.15.0:
https://astral.sh/blog/ruff-v0.15.0

0.15.0 release on GitHub:
https://github.com/astral-sh/ruff/releases/tag/0.15.0

Author: generalmimon

.github/workflows/check-style.yml

@@ -20,7 +20,7 @@ jobs:
         id: install-ruff
         uses: astral-sh/ruff-action@v3
         with:
-          version: '0.14.x'
+          version: '0.15.x'
           args: '--version'
 
       - name: Run Ruff's linter - statistics