Instruction to cache while not using Github native cache

[tetienne]

Hi,

Having built-in cache feature is really great. Sadly, it means using the Github cache. While using Github Action Github runner, we may want to store the cache somewhere else, like for instance AWS S3.
In such case, a useful action is https://github.com/runs-on/cache which have the same interface than the native cache.

My question is the following: what are the path(s) to cache, and which restore and save keys? Looking at the code, it looks like this last part is not really straightforward.