Log Message:
terraform-provider-vultr: Update to version 2.2.0

Upstream release notes:

 v2.2.0
  - Updated to Go 1.16 to support darwin_arm64

 v2.1.4
  - Fix issue with vultr_instance.reserved_ip_id and
    vultr_reserved_ip.attached_id conflicting

 v2.1.3
  - updated terraform-plugin-sdk to v1.8.0 -> v2.4.0