Update Mocha

packages/sol-compiler/package.json

@@ -45,7 +45,6 @@
     "devDependencies": {
         "@0x/dev-utils": "^2.2.5",
         "@0x/tslint-config": "^3.0.1",
-        "@types/chokidar": "^1.7.5",
         "@types/mkdirp": "^0.5.2",
         "@types/pluralize": "^0.0.29",
         "@types/require-from-string": "^1.2.0",
@@ -57,7 +56,7 @@
         "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",
         "shx": "^0.2.2",
@@ -79,7 +78,7 @@
         "@0x/web3-wrapper": "^6.0.8",
         "@types/yargs": "^11.0.0",
         "chalk": "^2.3.0",
-        "chokidar": "^2.0.4",
+        "chokidar": "^3.0.2",
         "ethereum-types": "^2.1.4",
         "ethereumjs-util": "^5.1.1",
         "lodash": "^4.17.11",