Improve upstream CI report

[jrbourbeau]

xarray has a nice xarray-contrib/issue-from-pytest-log GitHub action for opening / updating an issue when there's a CI failure. This action fully covers all the existing functionality of our current report job in the upstream build but has a couple of additional benefits:

1. We get a list of failing tests / exceptions directly in the issue that's opened (see this issue which was opened up by this PR as an example)
2. We no longer need maintain GitHub script code. This can be maintained by xarray-contrib/issue-from-pytest-log

cc @charlesbluca for thoughts

[charlesbluca]

Thanks @jrbourbeau! Just one question

[jrbourbeau]

Thanks @charlesbluca! Let's give this a try on main

[jrbourbeau]

Note that #9204 was updated and now has tests and exceptions listed