Update dependency config to v3.1.0

package-lock.json

@@ -3282,9 +3282,9 @@
       }
     },
     "config": {
-      "version": "3.0.1",
-      "resolved": "https://registry.npmjs.org/config/-/config-3.0.1.tgz",
-      "integrity": "sha512-TBNrrk2b6AybUohqXw2AydglFBL9b/+1GG93Di6Fm6x1SyVJ5PYgo+mqY2X0KpU9m0PJDSbFaC5H95utSphtLw==",
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/config/-/config-3.1.0.tgz",
+      "integrity": "sha512-t6oDeNQbsIWa+D/KF4959TANzjSHLv1BA/hvL8tHEA3OUSWgBXELKaONSI6nr9oanbKs0DXonjOWLcrtZ3yTAA==",
       "dev": true,
       "requires": {
         "json5": "^1.0.1"

package.json

@@ -29,7 +29,7 @@
     "chai": "4.2.0",
     "chai-as-promised": "7.1.1",
     "chromedriver": "2.46.0",
-    "config": "3.0.1",
+    "config": "3.1.0",
     "cross-env": "5.2.0",
     "eslint": "5.16.0",
     "eslint-config-wpcalypso": "4.0.1",