Update vendor directory

Re-added cobra patch 499475bb41

vendor/golang.org/x/net/http2/pipe.go

@@ -10,7 +10,7 @@ import (
 	"sync"
 )
 
-// pipe is a goroutine-safe io.Reader/io.Writer pair.  It's like
+// pipe is a goroutine-safe io.Reader/io.Writer pair. It's like
 // io.Pipe except there are no PipeReader/PipeWriter halves, and the
 // underlying buffer is an interface. (io.Pipe is always unbuffered)
 type pipe struct {