ng : File C:\Users\Lenovo\AppData\Roaming\npm\ng.ps1 cannot be loaded. The file C:\Users\Lenovo\AppData\Roaming\npm\ng.ps1 is not digitally signed. You cannot run
this script on the current system. For more information about running scripts and setting execution policy, see about_Execution_Policies at
https:/go.microsoft.com/fwlink/?LinkID=135170.
At line:1 char:1
+ ng serve
+ ~~
+ CategoryInfo : SecurityError: (:) [], PSSecurityException
+ FullyQualifiedErrorId : UnauthorizedAccess
当执行ng serve时出现错误,请问如何解决?