Update generator dependencies (#432)

* Fixes #431

* Use only LTS versions of Node, ensure compatibility with ESLint

.travis.yml

@@ -1,7 +1,6 @@
 language: node_js
 node_js:
   - "10"
-  - "9"
   - "8"
 addons:
   apt:

generators/app/templates/package.json

@@ -98,7 +98,7 @@
     "normalize-scss": "^7.0.1"
   },
   "engines": {
-    "node": ">=8"
+    "node": "^8.10.0 || ^10.13.0"
   },
   "pre-commit": [
     "lint"

package.json

@@ -27,25 +27,25 @@
     "prepublish": "php -r \"copy('https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar', 'helpers/wp-cli.phar'); if(!file_exists('helpers/wp-cli.phar')) exit(1);\""
   },
   "dependencies": {
-    "async": "^2.6.1",
-    "chalk": "^2.4.1",
+    "async": "^2.6.3",
+    "chalk": "^2.4.2",
     "command-exists": "^1.2.8",
-    "fs-extra": "^7.0.1",
+    "fs-extra": "^8.1.0",
     "limax": "^1.7.0",
-    "lodash": "^4.17.11",
-    "mysql": "^2.16.0",
-    "update-notifier": "^2.5.0",
-    "yeoman-generator": "^3.1.1"
+    "lodash": "^4.17.15",
+    "mysql": "^2.17.1",
+    "update-notifier": "^3.0.1",
+    "yeoman-generator": "^4.0.1"
   },
   "devDependencies": {
     "cross-spawn": "^6.0.5",
-    "eslint": "^5.16.0",
-    "mocha": "^5.2.0",
+    "eslint": "^6.1.0",
+    "mocha": "^6.2.0",
     "yeoman-assert": "^3.1.1",
-    "yeoman-test": "^1.9.1"
+    "yeoman-test": "^2.0.0"
   },
   "engines": {
-    "node": ">=8"
+    "node": "^8.10.0 || ^10.13.0"
   },
   "repository": "[email protected]:xfiveco/generator-chisel.git",
   "license": "MIT"