Cache vcpkg binary cache for macOS

[mrotteveel]

Due to microsoft/vcpkg-tool#1662, the original caching is no longer working.

[mrotteveel]

@asfernandes Do you think generating the key based on the contents of vcpkg-custom is sufficient, or do you think I should take anything else into consideration?

[asfernandes]

I don't think you need to hash vcpkg-custom. vcpkg will hash things by hemself.

[asfernandes]

From one side, vcpkg handles all things about differences with its own hashing, so it would be a matter of get and update the cache.
From another side, that would accumulate things when we start to change versions (vcpkg, libraries, custom ports).
You don't need to hash the git submodule. We have a reference of it in vcpkg-configuration.json. So we can hash it and maybe vcpkg.json too.

[mrotteveel]

From one side, vcpkg handles all things about differences with its own hashing, so it would be a matter of get and update the cache. From another side, that would accumulate things when we start to change versions (vcpkg, libraries, custom ports). You don't need to hash the git submodule. We have a reference of it in vcpkg-configuration.json. So we can hash it and maybe vcpkg.json too.

In the current setup, even if the hash changes, it will fetch a previous version of the cache, so accumulation can occur here as well (but I consider that not so big a problem, or we can sometimes do some manual cache maintenance by deleting (all) caches).

In any case, I'll add vcpkg-configuration.json and vcpkg.json to the hash (and remove vcpkg/**).

Sidequest: I noticed that vcpkg.json has "version-string": "5.0.0". Should that be updated to 6.0.0?

[mrotteveel]

@asfernandes I think this is good to go. Do you agree?

[mrotteveel]

I'll also apply these changes to v5.0-release.