Remove conda caching in CI

[altheaden]

In this PR, I've removed the conda caching job from the build workflow. This will hopefully fix the random CI crashing errors we're seeing across many repos right now.

Checklist

• Testing comment in the PR documents testing used to verify the changes

[altheaden]

Testing

I tested this with a couple of runs on my fork of mache, but it's not really possible to say if it is actually fixed since it appears to happen semi-randomly. We'll have to wait and see as we do more testing in general if it's really fixed.

[altheaden]

@xylar I noticed that we also use caching in the docs workflow. Obv since it's only one job we don't have the race condition issue that we (most likely) have here, but generally speaking do you think it is useful to keep the caching in the docs workflow or should I remove that in this PR also?

[xylar]

Yes, please also make a PR to remove caching from the docs workflow, just in case. You can combine them into one PR on other repos (e.g. compass and polaris).

[xylar]

@altheaden, thanks for doing this and especially for the testing!