Cleanup Snapclient includes

client/decoder/pcm_decoder.hpp

@@ -1,6 +1,6 @@
 /***
     This file is part of snapcast
-    Copyright (C) 2014-2020  Johannes Pohl
+    Copyright (C) 2014-2024  Johannes Pohl
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -16,8 +16,9 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ***/
 
-#ifndef PCM_DECODER_H
-#define PCM_DECODER_H
+#pragma once
+
+// local headers
 #include "decoder.hpp"
 
 
@@ -33,5 +34,3 @@ public:
 };
 
 } // namespace decoder
-
-#endif