Add @typescript-eslint/prefer-as-const rule

https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/prefer-as-const.md

Author: sindresorhus

index.js

@@ -332,6 +332,7 @@ module.exports = {
 		'no-useless-constructor': 'off',
 		'@typescript-eslint/no-useless-constructor': 'error',
 		'@typescript-eslint/no-var-requires': 'error',
+		'@typescript-eslint/prefer-as-const': 'error',
 		'@typescript-eslint/prefer-for-of': 'error',
 		'@typescript-eslint/prefer-function-type': 'error',
 		'@typescript-eslint/prefer-includes': 'error',