darwin_arm64 support

[etolbakov]

Hi @carlpett ,
thank you very much for this project!

Could you please add support for darwin_arm64?
Here's the error that I see when trying to perform terraform init for my project

╷
│ Error: Incompatible provider version
│ 
│ Provider registry.terraform.io/carlpett/sops v0.6.2 does not have a package available for your current platform, darwin_arm64.

Thank you very much!

Regards, Eugene