Cache poetry installation itself

[abatilo]

Cache poetry installation itself

[dmwyatt]

FWIW, this action takes around 30 seconds for me on windows-latest.

I care about this in one main situation that is not uncommon for me:

When I'm actively working on my GitHub workflow and trying out different things...I have to wait the 30 seconds for every time make a change.

From the standpoint of any individual workflow this does not happen terribly often, but from the standpoint of someone like me who works on many workflows across many projects it's a lot of waiting.

[abatilo]

Thanks for the suggestion @yajo

After experimenting with this in #37 two things became apparent to me.

1. By using pip we don't have to worry about which platform we're running on
2. Installing/downloading through pip only costs somewhere between 5-15 seconds. Since GitHub Action minutes are usually rounded up to the nearest minute, I'm not really sure if there's that much reason to go for the speed up.

If you disagree, please let me know! Otherwise, I'm going to close this issue.

[threeal]

Hi, can we reopen this issue? I have another suggestion to caching the Poetry itself by installing it inside a virtual environment and caching the folder of that virtual environment, as described in this documentation.