These registry settings affect .NET Framework 4+ and therefore PowerShell. Set them and restart any PowerShell sessions to use latest TLS, no reboot needed.
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
Set-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\.NetFramework\v4.0.30319' -Name 'SchUseStrongCrypto' -Value '1' -Type DWord
See https://docs.microsoft.com/en-us/dotnet/framework/network-programming/tls#schusestrongcrypto