Crop Decimate Node: On Parameter Set

[mhubii]

Thank you for providing this great package.

I believe dynamic parameters are not supported in

https://github.com/ros-perception/image_pipeline/blob/rolling/image_proc/src/crop_decimate.cpp

[ahcorde]

There is no support for now, but happy to review a PR if you decide to contribute

[mhubii]

Would the PR aim at rolling?

[ahcorde]

@mhubii yes, and we can backport the changes later if the PR doesn´t break ABI or API