Update dependency eslint-plugin-import to v2.21.0

Author: renovate-bot

package.json

@@ -101,7 +101,7 @@
     "eslint-config-airbnb": "18.1.0",
     "eslint-config-prettier": "6.11.0",
     "eslint-loader": "4.0.2",
-    "eslint-plugin-import": "2.20.2",
+    "eslint-plugin-import": "2.21.0",
     "eslint-plugin-jest": "23.13.2",
     "eslint-plugin-jsx-a11y": "6.2.3",
     "eslint-plugin-prettier": "3.1.3",