Shaking out dependencies is a normal part of releasing a package for the first time. You're in good company. It might be worth checking your CMake configuration for any other dependencies that aren't declared to cut down on the amount of point releases you need to make.
The initial crystal release failed to build due to a missing dependency on rosidl_default_generators.
You can check the build log for more info http://build.ros2.org/job/Cbin_uB64__system_modes__ubuntu_bionic_amd64__binary/1/
Shaking out dependencies is a normal part of releasing a package for the first time. You're in good company. It might be worth checking your CMake configuration for any other dependencies that aren't declared to cut down on the amount of point releases you need to make.