Update dependency mocha to v5.1.1 (#136)

Author: renovate[bot]

package-lock.json

@@ -23,7 +23,7 @@
     "babel-preset-es2015": "6.24.1",
     "babel-preset-stage-0": "6.24.1",
     "eslint": "4.19.1",
-    "mocha": "5.1.0",
+    "mocha": "5.1.1",
     "graphql": "0.13.2",
     "graphql-tools": "2.24.0",
     "test-all-versions": "3.3.2"