Update google.golang.org/grpc from v1.27.1 to v1.38.0

v1.38.0 is used by Kubernetes since
https://github.com/kubernetes/kubernetes/pull/100488.

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

vendor/google.golang.org/grpc/encoding/encoding.go

@@ -19,7 +19,10 @@
 // Package encoding defines the interface for the compressor and codec, and
 // functions to register and retrieve compressors and codecs.
 //
-// This package is EXPERIMENTAL.
+// Experimental
+//
+// Notice: This package is EXPERIMENTAL and may be changed or removed in a
+// later release.
 package encoding
 
 import (
@@ -46,10 +49,15 @@ type Compressor interface {
 	// coding header.  The result must be static; the result cannot change
 	// between calls.
 	Name() string
-	// EXPERIMENTAL: if a Compressor implements
+	// If a Compressor implements
 	// DecompressedSize(compressedBytes []byte) int, gRPC will call it
 	// to determine the size of the buffer allocated for the result of decompression.
 	// Return -1 to indicate unknown size.
+	//
+	// Experimental
+	//
+	// Notice: This API is EXPERIMENTAL and may be changed or removed in a
+	// later release.
 }
 
 var registeredCompressor = make(map[string]Compressor)