No need to put a version on the plugins

Index: cmake/macros.cmake
--- cmake/macros.cmake.orig
+++ cmake/macros.cmake
@@ -162,8 +162,6 @@ macro(PDAL_ADD_PLUGIN _name _type _shortname)
 
     set_property(TARGET ${${_name}} PROPERTY FOLDER "Plugins/${_type}")
     set_target_properties(${${_name}} PROPERTIES
-        VERSION "${PDAL_BUILD_VERSION}"
-        SOVERSION "${PDAL_API_VERSION}"
         CLEAN_DIRECT_OUTPUT 1)
 
     install(TARGETS ${${_name}}
