[relay] Use new upstream for nhooyr.io/websocket package (#3287)

The nhooyr.io/websocket package was renamed to github.com/coder/websocket when
the project was transferred to "coder" as the new maintainer.

Use the new import path and update go.mod and go.sum accordingly.

Signed-off-by: Christian Stewart <christian@aperture.us>

relay/server/listener/ws/conn.go

@@ -9,7 +9,7 @@ import (
 	"time"
 
 	log "github.com/sirupsen/logrus"
-	"nhooyr.io/websocket"
+	"github.com/coder/websocket"
 )
 
 const (

relay/server/listener/ws/listener.go

@@ -9,7 +9,7 @@ import (
 	"net/http"
 
 	log "github.com/sirupsen/logrus"
-	"nhooyr.io/websocket"
+	"github.com/coder/websocket"
 )
 
 // URLPath is the path for the websocket connection.