* Update to master

This introduces a new type `CollatorId`, currently just `SessionKey`
but which would forseeably change to its own thing. It seems to work
like this (despite there being a lot of the new-incompatible
`AccountId` replaced). No idea if it does anything sensible, though.

* Cleanups

* Fix tests

* Remove commented code

* Specify commit hash

* Remove commented code

* Correct version

* Update runtime/Cargo.toml

Co-Authored-By: gavofyork <[email protected]>

* PairT instead of _Pair

* Update lock file

* Remove rev causing upset