Downgrade `strip-ansi` to 3.0.1 (#2860)

See: https://github.com/facebookincubator/create-react-app/pull/2692

package.json

@@ -89,7 +89,7 @@
     "recursive-copy": "^2.0.6",
     "send": "^0.15.3",
     "source-map-support": "0.4.15",
-    "strip-ansi": "4.0.0",
+    "strip-ansi": "3.0.1",
     "styled-jsx": "^1.0.8",
     "touch": "3.1.0",
     "unfetch": "3.0.0",