Enable cache on the pipeline

[Kludex]

There was a previous discussion about this: encode/httpx#1680

One of the goals is to reduce the time on the pipeline, the other is to reduce the amount of networking resources. 🙏

There were no arguments against this, only a note (my own) about the fact that we always need to install the latest dependencies from the setup.py (now pyproject.toml).

The thing is that the cache entry is removed (if not used) after 7 days, see here. Also, once a month we have updates via Dependabot on the requirements.txt, which triggers a new cache entry. Which means once a month we'll have the latest uvicorn dependencies - I think it's reasonable.

[tomchristie]

Hrm.

Problem with dependancy caching is that it tends to make it more awkward to track down dependancy breakages when they do occur. Let's consider humans time as the priority here...

Do the sometimes faster test results benefit us more than the "was this with or without the cache? we'd like to test with a flushed cache. etc."

My inclination would be that it's probably not an overall benefit to us as a team, from that perspective.

What do we think?

[Kludex]

I'm perfectly fine with that reasoning. 🙏

More than anything, I wanted to have a closure on this matter.

Thanks @tomchristie 👍