Auto update nightly-next dependencies that don't use next protocol flags using branches.

[sisuresh]

For the dependencies that don't use feature gating flags, we should agree on branch names for the next protocol, and have nightly-next auto update. This will force us to create those branches and start integration sooner.

Also look into adding feature gating flags in these projects.

[leighmcculloch]

Started conversation with the @stellar/platform-eng team here about moving away from using short lived release branches and doing next work in a stable location.