Fixed linting issues

app.go

@@ -322,7 +322,8 @@ func (h *Headscale) expireEphemeralNodesWorker() {
 func (h *Headscale) grpcAuthenticationInterceptor(ctx context.Context,
 	req interface{},
 	info *grpc.UnaryServerInfo,
-	handler grpc.UnaryHandler) (interface{}, error) {
+	handler grpc.UnaryHandler,
+) (interface{}, error) {
 	// Check if the request is coming from the on-server client.
 	// This is not secure, but it is to maintain maintainability
 	// with the "legacy" database-based client

derp_server.go

@@ -122,7 +122,7 @@ func (h *Headscale) DERPHandler(ctx *gin.Context) {
 
 	if !fastStart {
 		pubKey := h.privateKey.Public()
-		pubKeyStr := pubKey.UntypedHexString() // nolint
+		pubKeyStr := pubKey.UntypedHexString()
 		fmt.Fprintf(conn, "HTTP/1.1 101 Switching Protocols\r\n"+
 			"Upgrade: DERP\r\n"+
 			"Connection: Upgrade\r\n"+