Fix typo detected by codespell + add codespell workflow to avoid typos sneaking in

.codespellrc

@@ -0,0 +1,2 @@
+[codespell]
+skip = .git

.github/workflows/codespell.yml

@@ -0,0 +1,19 @@
+---
+name: Codespell
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+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@v1

README.md

@@ -231,7 +231,7 @@ This means that in example above we would request ```/ping``` once again in case
 
 ### Types
 
-`aiohttp_retry` is a typed project. It should be fully compatablie with mypy.
+`aiohttp_retry` is a typed project. It should be fully compatible with mypy.
 
 It also introduce one special type:
 ```