Bump required oxenmq version

Current lokinet dev relies on something from oxenmq dev branch which is
in the not-yet-released next version; without this lokinet tries using
the system 1.2.3 install, which then fails the build.

CMakeLists.txt

@@ -164,7 +164,7 @@ endif()
 
 option(FORCE_OXENMQ_SUBMODULE "force using oxenmq submodule" OFF)
 if(NOT FORCE_OXENMQ_SUBMODULE)
-  pkg_check_modules(OXENMQ liboxenmq>=1.2.2)
+  pkg_check_modules(OXENMQ liboxenmq>=1.2.4)
 endif()
 if(OXENMQ_FOUND)
   add_library(oxenmq INTERFACE)