all: change module to google.golang.org/protobuf

Temporarily remove go.mod, since we can't generate an accurate one until
the corresponding v1 change is submitted.

Change-Id: I1e1ad97f2b455e33f61ffaeb8676289795e47e72
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/177000
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
diff --git a/encoding/jsonpb/bench_test.go b/encoding/jsonpb/bench_test.go
index eba4119..3dcc5e0 100644
--- a/encoding/jsonpb/bench_test.go
+++ b/encoding/jsonpb/bench_test.go
@@ -7,8 +7,8 @@
 import (
 	"testing"
 
-	"github.com/golang/protobuf/v2/encoding/jsonpb"
-	knownpb "github.com/golang/protobuf/v2/types/known"
+	"google.golang.org/protobuf/encoding/jsonpb"
+	knownpb "google.golang.org/protobuf/types/known"
 )
 
 func BenchmarkUnmarshal_Duration(b *testing.B) {