add shareable eslint config

Author: szaleq

config/.eslintrc.json

@@ -1,3 +1,3 @@
 {
-  "extends": [ "plugin:@wordpress/eslint-plugin/recommended" ]
+	"extends": "../eslint-config"
 }

eslint-config.js

@@ -0,0 +1,23 @@
+module.exports = {
+	extends: ['plugin:@wordpress/eslint-plugin/recommended'],
+	parserOptions: {
+		requireConfigFile: false,
+	},
+	rules: {
+		'prettier/prettier': [
+			'error',
+			{
+				useTabs: true,
+				tabWidth: 4,
+				printWidth: 80,
+				singleQuote: true,
+				trailingComma: 'es5',
+				bracketSpacing: true,
+				parenSpacing: false,
+				bracketSameLine: false,
+				semi: true,
+				arrowParens: 'always',
+			},
+		],
+	},
+};