chore(deps): update dependency imgur to v2

Author: renovate-bot

package.json

@@ -59,7 +59,7 @@
     "flow-bin": "0.135.0",
     "fs-extra": "^4.0.2",
     "imagemagick": "^0.1.3",
-    "imgur": "^0.2.1",
+    "imgur": "^2.0.0",
     "memory-fs": "^0.4.1",
     "mocha": "^4",
     "mocketeer": "^0.3.0",