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/internal/impl/legacy_export.go b/internal/impl/legacy_export.go
index 8038333..f08f242 100644
--- a/internal/impl/legacy_export.go
+++ b/internal/impl/legacy_export.go
@@ -10,8 +10,8 @@
 	"hash/crc32"
 	"math"
 
-	"github.com/golang/protobuf/v2/internal/errors"
-	pref "github.com/golang/protobuf/v2/reflect/protoreflect"
+	"google.golang.org/protobuf/internal/errors"
+	pref "google.golang.org/protobuf/reflect/protoreflect"
 )
 
 // These functions exist to support exported APIs in generated protobufs.