fixup! chore: remove support for vue-cli-service e2e registerCommand (#3774)

Author: haoqunjiang

packages/@vue/cli-plugin-e2e-cypress/index.js

@@ -47,13 +47,6 @@ module.exports = (api, options) => {
 
     return runner
   })
-
-  // TODO remove in RC
-  api.registerCommand('e2e', (args, rawArgv) => {
-    const { warn } = require('@vue/cli-shared-utils')
-    warn(`Deprecation Warning: "vue-cli-service e2e" has been renamed to "vue-cli-service test:e2e".`)
-    return api.service.run('test:e2e', args, rawArgv)
-  })
 }
 
 module.exports.defaultModes = {