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/proto/decode_gen.go b/proto/decode_gen.go
index 1a3ef15..36071e7 100644
--- a/proto/decode_gen.go
+++ b/proto/decode_gen.go
@@ -10,9 +10,9 @@
 	"math"
 	"unicode/utf8"
 
-	"github.com/golang/protobuf/v2/internal/encoding/wire"
-	"github.com/golang/protobuf/v2/internal/errors"
-	"github.com/golang/protobuf/v2/reflect/protoreflect"
+	"google.golang.org/protobuf/internal/encoding/wire"
+	"google.golang.org/protobuf/internal/errors"
+	"google.golang.org/protobuf/reflect/protoreflect"
 )
 
 // unmarshalScalar decodes a value of the given kind.