Revert "Update node-sass"

This reverts commit f410ea9.

Author: iwatakeshi

package.json

@@ -88,7 +88,7 @@
     "eslint-plugin-react": "^7.12.4",
     "express": "^4.14.1",
     "jest": "^24.0.1",
-    "node-sass": "^5.0.0",
+    "node-sass": "^4.5.0",
     "react": "^16.8.0",
     "react-dom": "^17.0.1",
     "react-test-renderer": "^17.0.1",