without this find_dependency() doesn't exist
--
diff --git a/cmake/gRPCConfig.cmake.in b/cmake/gRPCConfig.cmake.in
index 98d8c6d..5500ca2 100644
--- a/cmake/gRPCConfig.cmake.in
+++ b/cmake/gRPCConfig.cmake.in
@@ -1,5 +1,6 @@
 # Module path
 list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/modules)
+include(CMakeFindDependencyMacro)
 
 # Depend packages
 @_gRPC_FIND_ZLIB@