## Issue Addressed
Closes#1504Closes#1505
Replaces #1703Closes#1707
## Proposed Changes
* Update BLST and Milagro to versions compatible with BLSv4 spec
* Update Lighthouse to spec v1.0.0-rc.0, and update EF test vectors
* Use the v1.0.0 constants for `MainnetEthSpec`.
* Rename `InteropEthSpec` -> `V012LegacyEthSpec`
* Change all constants to suit the mainnet `v0.12.3` specification (i.e., Medalla).
* Deprecate the `--spec` flag for the `lighthouse` binary
* This value is now obtained from the `config_name` field of the `YamlConfig`.
* Built in testnet YAML files have been updated.
* Ignore the `--spec` value, if supplied, log a warning that it will be deprecated
* `lcli` still has the spec flag, that's fine because it's dev tooling.
* Remove the `E: EthSpec` from `YamlConfig`
* This means we need to deser the genesis `BeaconState` on-demand, but this is fine.
* Swap the old "minimal", "mainnet" strings over to the new `EthSpecId` enum.
* Always require a `CONFIG_NAME` field in `YamlConfig` (it used to have a default).
## Additional Info
Lots of breaking changes, do not merge! ~~We will likely need a Lighthouse v0.4.0 branch, and possibly a long-term v0.3.0 branch to keep Medalla alive~~.
Co-authored-by: Kirk Baird <baird.k@outlook.com>
Co-authored-by: Paul Hauner <paul@paulhauner.com>
## Issue Addressed
#1464
## Proposed Changes
Increase the slog-async log channel size from the default of 128 to 2048 to reduce the number of dropped logs.
## Additional Info
