Update stylelint to version 12.0.0

package.json

@@ -113,7 +113,7 @@
     "prettier": "^1.17.1",
     "pro-download": "1.0.1",
     "serverless-http": "^2.0.2",
-    "stylelint": "^10.1.0",
+    "stylelint": "^12.0.0",
     "umi-plugin-ga": "^1.1.3",
     "umi-plugin-pro": "^1.0.2",
     "umi-types": "^0.5.0"