chore(ci): Replace flake8 job with ruff

Author: effigies

.github/workflows/validate.yml

@@ -17,11 +17,12 @@ permissions:
   contents: read
 
 jobs:
-  flake8:
+  style:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
-    - run: pipx run flake8-pyproject sdcflows/
+    - run: pipx run ruff check sdcflows/
+    - run: pipx run ruff format --diff sdcflows/
 
   # codespell:
   #   runs-on: ubuntu-latest