feat: add --no-fix-warnings option (#3307)

Author: haoqunjiang

packages/@vue/cli-plugin-eslint/index.js

@@ -61,7 +61,8 @@ module.exports = (api, options) => {
     usage: 'vue-cli-service lint [options] [...files]',
     options: {
       '--format [formatter]': 'specify formatter (default: codeframe)',
-      '--no-fix': 'do not fix errors',
+      '--no-fix': 'do not fix errors or warnings',
+      '--no-fix-warnings': 'fix errors, but do not fix warnings',
       '--max-errors [limit]': 'specify number of errors to make build failed (default: 0)',
       '--max-warnings [limit]': 'specify number of warnings to make build failed (default: Infinity)'
     },

packages/@vue/cli-plugin-eslint/lint.js

@@ -32,6 +32,10 @@ module.exports = function lint (args = {}, api) {
     cwd
   }, argsConfig)
 
+  const noFixWarnings = (argsConfig.fixWarnings === false)
+  const noFixWarningsPredicate = (lintResult) => lintResult.severity === 2
+  config.fix = config.fix && (noFixWarnings ? noFixWarningsPredicate : true)
+
   if (!fs.existsSync(api.resolve('.eslintignore'))) {
     // .eslintrc.js files (ignored by default)
     // However, we need to lint & fix them so as to make the default generated project's