Fixed pkg-config Version

Author: dvigne

pkg-config/jsoncpp.pc.in

@@ -5,7 +5,7 @@ includedir=@includedir_for_pc_file@
 
 Name: jsoncpp
 Description: A C++ library for interacting with JSON
-Version: @JSONCPP_VERSION@
+Version: @PROJECT_VERSION@
 URL: https://github.com/open-source-parsers/jsoncpp
 Libs: -L${libdir} -ljsoncpp
 Cflags: -I${includedir}