chore: Dropped support of Node.js 4

Some NPM dependencies dropped support of Node.js 4. It is easier to drop it
too, that looking for workarounds to get the testing build running, or claim
the support without actually testing it.

Add testing with Node.js 10.

BREAKING CHANGE: Dropped support of Node.js 4

Author: prantlf

.travis.yml

@@ -6,9 +6,9 @@ cache:
 notifications:
   email: false
 node_js:
+  - '10'
   - '8'
   - '6'
-  - '4'
 before_install:
   - npm install -g npm
 before_script:

README.md

@@ -167,6 +167,7 @@ your code using Grunt.
 
 ## Release History
 
+ * 2018-04-27   v1.0.0   Dropped support of Node.js 4
  * 2018-03-06   v0.1.0   Write report to a file as JSON
  * 2018-02-26   v0.0.1   Initial release
 

package.json

@@ -35,7 +35,7 @@
     "semantic-release": "semantic-release"
   },
   "dependencies": {
-    "chalk": "^2.3.1",
+    "chalk": "^2.4.1",
     "mkdirp": "^0.5.1",
     "libtidy": "^0.3.7"
   },
@@ -49,8 +49,8 @@
     "grunt-istanbul": "^0.8.0",
     "grunt-standard": "^3.1.0",
     "nsp": "^3.2.1",
-    "travis-deploy-once": "^4.3.4",
-    "semantic-release": "^15.0.0"
+    "travis-deploy-once": "^4.4.1",
+    "semantic-release": "^15.1.7"
   },
   "keywords": [
     "gruntplugin",