chore(package): update fetch-mock to version 7.2.0

Closes #51

Author: greenkeeper[bot]

package.json

@@ -66,7 +66,7 @@
     "cz-conventional-changelog": "^2.0.0",
     "eslint": "^5.1.0",
     "eslint-plugin-ava": "^4.2.2",
-    "fetch-mock": "^6.5.0",
+    "fetch-mock": "^7.2.0",
     "husky": "^0.14.3",
     "nyc": "^12.0.2",
     "rimraf": "^2.6.2",