Gulp.ps1 cannot be loaded. The file not digitally signed. You cannot run this script on the current system.

This security error can occur when the PowerShell's execution policy is set to Allsigned or Remotesigned and the script isn't signed.

Check execution policy in Power Shell: Get-ExecutionPolicy and then Get-ExecutionPolicy – list

We can change the execution policy permanently or temporarily

Set-ExecutionPolicy unrestricted

Set-ExecutionPolicy -Scope Process -ExecutionPolicy Bypass

This command sets the execution policy to bypass for only the current PowerShell session, when you open again you may need to run again.