ci: adopt Danger with Sentry's shared config

[lcian]

Enables Danger with our shared config.
I prefer to be forced to write the changelog directly with each PR.

[lcian]

Okay it works, it looked like it wasn't working because a commit with ci scope doesn't require a changelog entry

[Swatinem]

well, if you must, why not :-D

I personally hate this, but I think it makes sense to actually enforce for a SDK repo (as opposed to symbolic/ator which had this set up, just to be a huge pain in the rear.

[lcian]

Yeah, no one is forcing me to enable it but personally I find it easier to do the changelog immediately rather than having to describe what I did later and requiring an additional PR.