[REF] Add pre-commit workflow

Author: legalsylvain

.github/workflows/pre-commit.yml

@@ -0,0 +1,36 @@
+name: pre-commit
+
+on:
+  pull_request:
+    branches:
+      - "*"
+  push:
+    branches:
+      - "master"
+
+jobs:
+  pre-commit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
+        with:
+          python-version: "3.8"
+      - name: Get python version
+        run: echo "PY=$(python -VV | sha256sum | cut -d' ' -f1)" >> $GITHUB_ENV
+      - uses: actions/cache@v1
+        with:
+          path: ~/.cache/pre-commit
+          key: pre-commit|${{ env.PY }}|${{ hashFiles('.pre-commit-config.yaml') }}
+      - name: Install pre-commit
+        run: pip install pre-commit
+      - name: Run pre-commit
+        run: pre-commit run --all-files --show-diff-on-failure --color=always
+      - name: Check that all files generated by pre-commit are in git
+        run: |
+          newfiles="$(git ls-files --others --exclude-from=.gitignore)"
+          if [ "$newfiles" != "" ] ; then
+              echo "Please check-in the following files:"
+              echo "$newfiles"
+              exit 1
+          fi