Add workflow to update pre-commit.yaml (#78)

fixes #33

.github/workflows/pre-commit-update.yaml

@@ -0,0 +1,45 @@
+name: Update template pre-commit
+permissions:
+    contents: write
+    pull-requests: write
+
+on:
+  # Allow manual runs through the web UI
+  workflow_dispatch:
+  schedule:
+    #        ┌───────── minute (0 - 59)
+    #        │ ┌───────── hour (0 - 23)
+    #        │ │ ┌───────── day of the month (1 - 31)
+    #        │ │ │ ┌───────── month (1 - 12 or JAN-DEC)
+    #        │ │ │ │ ┌───────── day of the week (0 - 6 or SUN-SAT)
+    - cron: '0 7 * * 1'  # Every Monday at 7am UTC
+
+jobs:
+  update:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - uses: actions/setup-python@v5
+
+      - name: Install pre-commit
+        run: pip install pre-commit
+
+      - name: Run pre-commit update
+        id: check
+        run: pre-commit autoupdate -c '{{ cookiecutter.package_name }}/.pre-commit-config.yaml'
+
+      - name: Create pull request
+        uses: peter-evans/create-pull-request@v6
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          delete-branch: true
+          branch-suffix: timestamp
+          title: "pre-commit updates in the template"
+          body: |
+            This is an autogenerated PR, which updates the `{{ cookiecutter.package_name }}/.pre-commit-config.yaml` file.

{{ cookiecutter.package_name }}/.pre-commit-config.yaml

@@ -1,3 +1,4 @@
+{# Note that this file must be valid yaml (and not only after rendering by jinja) so that pre-commit can autoupdate it. #}
 repos:
     # This should be before any formatting hooks like isort
   - repo: https://github.com/astral-sh/ruff-pre-commit