fix: correctly export makeJSOnlyValue

Author: merceyz

Diff for: packages/@vue/cli-plugin-eslint/eslintOptions.js

@@ -54,11 +54,12 @@ exports.config = (api, preset, rootOptions = {}) => {
 
 // __expression is a special flag that allows us to customize stringification
 // output when extracting configs into standalone files
-exports.makeJSOnlyValue = function makeJSOnlyValue (str) {
+function makeJSOnlyValue (str) {
   const fn = () => {}
   fn.__expression = str
   return fn
 }
+exports.makeJSOnlyValue = makeJSOnlyValue
 
 const baseExtensions = ['.js', '.jsx', '.vue']
 exports.extensions = api => api.hasPlugin('typescript')