changegroup: replace getchangegroup with makechangegroup As part of reducing the number of changegroup creation APIs, let's replace getchangegroup with calls to makechangegroup. This is mostly a drop in replacement, but it does change the version specifier to be required, so it's more obvious which callers are creating old version 1 changegroups still. Differential Revision: https://phab.mercurial-scm.org/D669