update actions/cache action to v4 (PyMySQL#684)

Author: renovate[bot]

.github/workflows/windows.yaml

@@ -15,7 +15,7 @@ jobs:
 
       - name: Cache Connector
         id: cache-connector
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: c:/mariadb-connector
           key: mariadb-connector-c-${{ env.CONNECTOR_VERSION }}-win