Add formatting CI job

Author: sjahr

.github/workflows/format.yaml

@@ -0,0 +1,26 @@
+# This is a format job. Pre-commit has a first-party GitHub action, so we use
+# that: https://github.com/pre-commit/action
+
+name: Formatting (pre-commit)
+
+on:
+  workflow_dispatch:
+  pull_request:
+  merge_group:
+  push:
+    branches:
+      - main
+
+jobs:
+  pre-commit:
+    name: Format
+    runs-on: ubuntu-22.04
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-python@v5
+      with:
+        python-version: '3.10'
+    - name: Install clang-format-14
+      run: sudo apt-get install clang-format-14
+    - uses: pre-commit/[email protected]
+      id: precommit