add codespell action

.github/workflows/codespell.yml

@@ -0,0 +1,15 @@
+name: codespell
+
+on:
+  pull_request:
+    branches: [main]
+
+jobs:
+  codespell:
+    name: Check for spelling errors
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Codespell
+        uses: codespell-project/actions-codespell@v2