build: Update linters

Change-Id: Ifebf6249a7b1b2bc909f9944895dfe680e7e1397

.eslintrc.json

@@ -1,8 +1,6 @@
 {
 	"root": true,
 	"extends": [
-		"wikimedia/client-es5",
-		"wikimedia/jquery",
-		"wikimedia/mediawiki"
+		"wikimedia/server"
 	]
 }

Gruntfile.js

@@ -3,10 +3,10 @@
  *
  * @package ContactPage
  */
+'use strict';
 
-/* eslint-env node */
 module.exports = function ( grunt ) {
-	var conf = grunt.file.readJSON( 'extension.json' );
+	const conf = grunt.file.readJSON( 'extension.json' );
 	grunt.loadNpmTasks( 'grunt-banana-checker' );
 	grunt.loadNpmTasks( 'grunt-eslint' );
 
@@ -17,7 +17,7 @@ module.exports = function ( grunt ) {
 				cache: true
 			},
 			all: [
-				'**/*.js{,on}',
+				'**/*.{js,json}',
 				'!node_modules/**',
 				'!vendor/**'
 			]

package.json

@@ -14,10 +14,10 @@
 		"@wdio/local-runner": "7.30.1",
 		"@wdio/mocha-framework": "7.26.0",
 		"@wdio/spec-reporter": "7.29.1",
-		"eslint-config-wikimedia": "0.25.0",
+		"eslint-config-wikimedia": "0.25.1",
 		"grunt": "1.6.1",
-		"grunt-banana-checker": "0.11.0",
-		"grunt-eslint": "24.0.1",
+		"grunt-banana-checker": "0.11.1",
+		"grunt-eslint": "24.3.0",
 		"wdio-mediawiki": "2.1.0"
 	}
 }