Get all Mocha's on same version and add typings to all packages

packages/0x.js/package.json

@@ -49,7 +49,7 @@
         "@0x/migrations": "^4.1.10",
         "@0x/tslint-config": "^3.0.1",
         "@types/lodash": "4.14.104",
-        "@types/mocha": "^2.2.42",
+        "@types/mocha": "^5.2.7",
         "@types/node": "*",
         "@types/sinon": "^2.2.2",
         "awesome-typescript-loader": "^5.2.1",
@@ -59,7 +59,7 @@
         "copyfiles": "^2.0.0",
         "dirty-chai": "^2.0.1",
         "make-promises-safe": "^1.1.0",
-        "mocha": "^4.1.0",
+        "mocha": "^6.2.0",
         "npm-run-all": "^4.1.2",
         "nyc": "^11.0.1",
         "opn-cli": "^3.1.0",