migrate to Buildhub2

[willkg]

yorstats uses Buildhub:

yorstats/yorstats/buildhub.py

Line 13 in 7ce2e94

'https://buildhub.prod.mozaws.net/v1/buckets/build-hub/collections/releases/search'

Buildhub is deprecated and will be decommissioned in July. See mozilla-services/buildhub#532 for details.

There are API docs here:

https://buildhub2.readthedocs.io/en/latest/user.html

This issue covers migrating crash-stop-addon to Buildhub2.

[willkg]

@calixteman Is this one of the things that we were talking about that you said wasn't used anymore? If not, I can throw together a PR.

[willkg]

Closing this out--it's super old.