Build script of dependency `eth2_network_config` is not run if building from cache

[dknopik]

Affected run with debug output: https://github.com/sigp/anchor/actions/runs/13116079748/job/36637757405?pr=122

I think what's happening here is that the caching does not include the /home/runner/.cargo/git directory, so it is created freshly. Then, cargo does not run the build.rs of eth2_network_config for some reason, so the genesis.ssz is not extracted from the freshly cloned repo.

We will need to either cache that directory, or force cargo to run the build.rs.

As a workaround, I'll open a PR to disable the cache.

[dknopik]

@magick93, replying here to your comment on the PR:

@dknopik - could this solve the issue? https://stackoverflow.com/a/53728256/265119

These solutions look good. Most would require changes in Lighthouse, and we want to avoid unnecessary rebuilds in other cases. There is also a nice suggestion in there to touch the build.rs file, but the problem is that the exact location of the build.rs file will vary, as Cargo stores them on a path it somehow generates. We've got to experiment a bit to find a good solution I think.