build: Updating eslint-config-wikimedia to 0.18.0

Additional changes:
* Added the "composer phan" command to conveniently run phan.
* Removing manual extensions for eslint.

Change-Id: I7eee67a7be3d74429f897dd165c268a8fd930b3a

Gruntfile.js

@@ -16,7 +16,6 @@ module.exports = function ( grunt ) {
 		banana: conf.MessagesDirs,
 		eslint: {
 			options: {
-				extensions: [ '.js', '.json' ],
 				cache: true
 			},
 			all: [

composer.json

@@ -15,6 +15,7 @@
 			"parallel-lint . --exclude vendor --exclude node_modules",
 			"phpcs -p -s",
 			"minus-x check ."
-		]
+		],
+		"phan": "phan -d . --long-progress-bar"
 	}
 }

package.json

@@ -4,7 +4,7 @@
 		"test": "grunt test"
 	},
 	"devDependencies": {
-		"eslint-config-wikimedia": "0.17.0",
+		"eslint-config-wikimedia": "0.18.0",
 		"grunt": "1.3.0",
 		"grunt-banana-checker": "0.9.0",
 		"grunt-eslint": "23.0.0",