refactor(go): go mod tidy

Author: sam

go.mod

@@ -1,3 +1,8 @@
 module github.com/celer-network/pb3-gen-sol
 
-require github.com/golang/protobuf v1.2.0
+go 1.15
+
+require (
+	github.com/golang/protobuf v1.2.0
+	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
+)

go.sum

@@ -1,2 +1,4 @@
 github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
 github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c h1:5KslGYwFpkhGh+Q16bwMP3cOontH8FOep7tGV86Y7SQ=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=