Go 1.13 supported

[gold-kou]

When Go 1.13 will be supported?

If it's fine, README might be fixed ✨

Using Protobuf validators is currently verified to work with:
Go 1.11 & 1.12

[Helcaraxan]

Hello @gold-kou. I'll update the README indeed. 1.13 should be supported already. 🙂

Thank you for raising the issue. 👍