Set up codespell (#3643)

.github/workflows/checks.yml

@@ -76,3 +76,14 @@ jobs:
       - name: Set up environment
         uses: ./.github/actions/setup
       - uses: crytic/slither-action@v0.1.1
+
+  codespell:
+    if: github.repository != 'OpenZeppelin/openzeppelin-contracts-upgradeable'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Run CodeSpell
+        uses: codespell-project/actions-codespell@v1.0
+        with:
+          check_filenames: true
+          skip: package-lock.json