Fix missing version in .pc file

Author: collares

doc/Doxyfile.in

@@ -1,5 +1,5 @@
 PROJECT_NAME           = "primesieve"
-PROJECT_NUMBER         = @PRIMESIEVE_VERSION@
+PROJECT_NUMBER         = @PROJECT_VERSION@
 INPUT                  = @PROJECT_SOURCE_DIR@/doc/mainpage.dox \
                          @PROJECT_SOURCE_DIR@/include/primesieve.hpp \
                          @PROJECT_SOURCE_DIR@/include/primesieve.h \

primesieve.pc.in

@@ -5,7 +5,7 @@ includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@
 
 Name: primesieve
 Description: Fast C/C++ prime number generator
-Version: @PRIMESIEVE_VERSION@
+Version: @PROJECT_VERSION@
 Libs: -L${libdir} -lprimesieve
 Libs.private: @CMAKE_THREAD_LIBS_INIT@
 Cflags: -I${includedir}