Remove version number from pureref binary

pureref.nix

@@ -10,6 +10,10 @@ appimageTools.wrapType1 rec {
     url = "https://www.pureref.com/download.php";
   };
 
+  extraInstallCommands = ''
+    mv $out/bin/${pname}-${version} $out/bin/${pname}
+  '';
+
   meta = with lib; {
     description = "Reference Image Viewer";
     homepage = "https://www.pureref.com";