Websockets: upgrade websocket libray to 1.4.1 (#21280)

vendor/github.com/gorilla/websocket/server.go

@@ -27,7 +27,7 @@ type Upgrader struct {
 	// HandshakeTimeout specifies the duration for the handshake to complete.
 	HandshakeTimeout time.Duration
 
-	// ReadBufferSize and WriteBufferSize specify I/O buffer sizes. If a buffer
+	// ReadBufferSize and WriteBufferSize specify I/O buffer sizes in bytes. If a buffer
 	// size is zero, then buffers allocated by the HTTP server are used. The
 	// I/O buffer sizes do not limit the size of the messages that can be sent
 	// or received.
@@ -153,7 +153,7 @@ func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeade
 
 	challengeKey := r.Header.Get("Sec-Websocket-Key")
 	if challengeKey == "" {
-		return u.returnError(w, r, http.StatusBadRequest, "websocket: not a websocket handshake: `Sec-WebSocket-Key' header is missing or blank")
+		return u.returnError(w, r, http.StatusBadRequest, "websocket: not a websocket handshake: 'Sec-WebSocket-Key' header is missing or blank")
 	}
 
 	subprotocol := u.selectSubprotocol(r, responseHeader)