chore(ci): update cache action

Author: abn

.github/workflows/main.yml

@@ -43,7 +43,7 @@ jobs:
         run: poetry config virtualenvs.in-project true
 
       - name: Set up cache
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         id: cache
         with:
           path: .venv