message: Bump wire protocol version for 4.2
diff: @@ -27,7 +27,7 @@ message ("mongocxx version: ${MONGOCXX_VERSION}")
  set(MONGOCXX_INLINE_NAMESPACE "v${MONGOCXX_ABI_VERSION}")
  set(MONGOCXX_HEADER_INSTALL_DIR "${CMAKE_INSTALL_INCLUDEDIR}/mongocxx/${MONGOCXX_INLINE_NAMESPACE}" CACHE INTERNAL "")
  -set(LIBMONGOC_REQUIRED_VERSION 1.13.0)
  +set(LIBMONGOC_REQUIRED_VERSION 1.15.0)
  set(LIBMONGOC_REQUIRED_ABI_VERSION 1.0)
  if(NOT MONGOCXX_LINK_WITH_STATIC_MONGOC)
  