prepare GA announcement

Author: iamqizhao

README.md

@@ -28,5 +28,5 @@ See [API documentation](https://godoc.org/google.golang.org/grpc) for package an
 
 Status
 ------
-Beta release
+GA
 

transport/http_util.go

@@ -53,7 +53,7 @@ import (
 
 const (
 	// The primary user agent
-	primaryUA = "grpc-go/0.11"
+	primaryUA = "grpc-go/1.0"
 	// http2MaxFrameLen specifies the max length of a HTTP2 frame.
 	http2MaxFrameLen = 16384 // 16KB frame
 	// http://http2.github.io/http2-spec/#SettingValues