heads-up: development branch is now "main"

[Andy Wingo]

Hi,

Just a heads-up that the main Guile development branch is now named
"main".

If you have a recent git and a fairly conventional setup, it will be
sufficient to switch your working copy by doing:

  git fetch origin
  git checkout main

Then you can continue to "git pull" as usual.

One note, the default branch that you get when you clone is currently
still "master".  This should be resolved soon.  In the meanwhile I will
keep "master" sync'd with "main".

Andy