Update to C++17 (#848)

Signed-off-by: Chris Lalancette <[email protected]>

Author: clalancette

ros2cli_test_interfaces/CMakeLists.txt

@@ -1,9 +1,10 @@
 cmake_minimum_required(VERSION 3.5)
 project(ros2cli_test_interfaces)
 
-# Default to C++14
+# Default to C++17
 if(NOT CMAKE_CXX_STANDARD)
-  set(CMAKE_CXX_STANDARD 14)
+  set(CMAKE_CXX_STANDARD 17)
+  set(CMAKE_CXX_STANDARD_REQUIRED ON)
 endif()
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(-Wall -Wextra -Wpedantic)