feat: update chokidar to v3

BREAKING CHANGE:

Massive CPU & RAM consumption improvements. 17x package & deps size reduction.

.travis.yml

@@ -5,11 +5,10 @@ cache:
 notifications:
   email: false
 node_js:
+  - '12'
   - '11'
   - '10'
   - '8'
-  - '6'
-  - '4'
 before_install:
   - if [ "$TRAVIS_PULL_REQUEST_BRANCH" == "" ]; then echo "//registry.npmjs.org/:_authToken=\${NPM_TOKEN}" >> .npmrc; fi
 after_success:

package.json

@@ -9,7 +9,7 @@
     "nodemon": "./bin/nodemon.js"
   },
   "engines": {
-    "node": ">=4"
+    "node": ">=8.10.0"
   },
   "repository": {
     "type": "git",
@@ -55,7 +55,7 @@
     "should": "~4.0.0"
   },
   "dependencies": {
-    "chokidar": "^2.1.8",
+    "chokidar": "^3.2.2",
     "debug": "^3.2.6",
     "ignore-by-default": "^1.0.1",
     "minimatch": "^3.0.4",