Add update checklist and ideally automate lotus version upgrades in Boost

We should ensure that we're updating lotus version across the various parts of Boost when we're upgrading.

It would be helpful to do an audit of the various places we're referencing Lotus, such as the Makefile, https://github.com/filecoin-project/boost/blob/v1.5.0/Makefile#L203, to create a checklist of things that needed to be updated for new versions.

Ideally we'd automate updating each of these, but we can start with a checklist to run through for things like releases.