* `SyncCommitteeIndex` -> `SyncSubcommitteeIndex`
* `syncCommitteePeriod` -> `sync_committee_period` (spec spelling)
* tighten period comparisons
* fix assert when validating committee message with non-altair state in
REST api
In tests, the private key was put into the validator deposit's withdraw
credentials so that it can be recovered later. This leads to problems
when creating the validators through other means that do not put the key
there. In general, mock private keys only depend on the validator index,
though, and because it is clear what the index of a validator is, it is
not actually needed to put the key into the credentials.
Jacek Sieka
Etan Kissling
tersec
Zahary Karadjov