This PR moves the cache's Git repo mirrors to all be stored under a new mirrors subdirectory, so that they won't need to be duplicated (and so that updating the mirror for a pallet also causes the mirror to be updated for that pallet as a repository).
This PR moves the cache's Git repo mirrors to all be stored under a new
mirrors
subdirectory, so that they won't need to be duplicated (and so that updating the mirror for a pallet also causes the mirror to be updated for that pallet as a repository).