feat(sgprotocgengoaiptest): bump to v0.31.0

https://github.com/einride/protoc-gen-go-aip-test/releases/tag/v0.31.0

Author: thall

tools/sgprotocgengoaiptest/tools.go

@@ -13,7 +13,7 @@ import (
 )
 
 const (
-	version = "0.30.4"
+	version = "0.31.0"
 	name    = "protoc-gen-go-aip-test"
 )