fix: pip cache key would be empty and couldn't use naked versions [APE-1179]

[antazoey]

fixes: #24
Fixes: APE-1179

1. fix: Fixes an issue where the GitHub action would not use an updated version of Ape when it existed when you excluded ape-version-pin. This was quite problematic and explains some anomalies we have seen. Basically, the cache key was just pip-38- and if you updated Ape, it would not care and would use the Ape from the cache.

To fix this, now, if you exclude ape-version-pin, we will lookup the latest version from pypi and use that rather than an empty pip install command. This way, we can properly cache the version ahead of time as well as check for the existence of the key. Now, when an Ape is released in between when a PR is first opened and when subsequent pushes to the PR's branch are done, it will update and use the newer Ape.

2. feat: Allows for setting versions without constraints. Before, if you tried to use 0.6.12 as the ape-version-pin value, it would error because it was expecting something like ==0.6.12. That is not always obvious. It is nice that we support that but it is weird to not allow naked versions as well. So this PR allows setting versions normally.

3. test: add test matrices for each of the parameter types you can provider for ape-version-pin. These tests helped me immensely (TDD).

4. chore: run prettier and add a .prettierrc to try and match the existing style

[antazoey]

and if you look at the test output for the (default) case, you will see the cache key is correctly including 0.6.12 in the key, so if 0.6.13 were to be released, it would not be a cache hit and would re-install ape

[fubuloubu]

Should probably release this as a new major?

[antazoey]

Should probably release this as a new major?

ok but let me try to fix a few other things first then