Add rmw_fastrtps_dynamic_cpp to the explicit group deps (#177)
Add rmw_fastrtps_dynamic_cpp to the explicit group deps (#177)

This package, which is in the same repository as rmw_fastrtps_cpp,
declares itself as a member of the rmw_implementation_packages group.
Fore completeness, and also because it is necessary for preresolved
groups to be comprehensive for RPM packaging purposes, the explicit
group list should contain this package.

Signed-off-by: Scott K Logan <8c724d14625be4be480086a9212b212477a303ef@cottsay.net>
ros2/rmw_implementation,ros2/rmw_implementation