fix: ensure new webpack5 generator property in rules passes ruleset checks (vuejs#1753)

close vuejs#1729

Co-authored-by: Thorsten Luenborg <t.luneborg@googlemail.com>

Author: LinusBorg

lib/plugin-webpack5.js

@@ -20,6 +20,7 @@ const ruleSetCompiler = new RuleSetCompiler([
   new BasicEffectRulePlugin('sideEffects'),
   new BasicEffectRulePlugin('parser'),
   new BasicEffectRulePlugin('resolve'),
+  new BasicEffectRulePlugin('generator'),
   new UseEffectRulePlugin()
 ])