Change release branch to emacs-28

* admin/notes/git-workflow:
* Makefile.in (PREFERRED_BRANCH): emacs-27 → emacs-28

Makefile.in

@@ -1165,7 +1165,7 @@ ChangeLog:
 	  ./$(emacslog) -o $(CHANGELOG) -n $(CHANGELOG_HISTORY_INDEX_MAX)
 
 # Check that we are in a good state for changing history.
-PREFERRED_BRANCH = emacs-27
+PREFERRED_BRANCH = emacs-28
 preferred-branch-is-current:
 	git branch | grep -q '^\* $(PREFERRED_BRANCH)$$'
 unchanged-history-files:

admin/notes/git-workflow

@@ -16,14 +16,14 @@ Initial setup
 
 Then we want to clone the repository.  We normally want to have both
 the current master and (if there is one) the active release branch
-(eg emacs-27).
+(eg emacs-28).
 
 mkdir ~/emacs
 cd ~/emacs
 git clone <membername>@git.sv.gnu.org:/srv/git/emacs.git master
 cd master
 git config push.default current
-git worktree add ../emacs-27 emacs-27
+git worktree add ../emacs-28 emacs-28
 
 You now have both branches conveniently accessible, and you can do
 "git pull" in them once in a while to keep updated.
@@ -67,7 +67,7 @@ which will look like
 
 commit 958b768a6534ae6e77a8547a56fc31b46b63710b
 
-cd ~/emacs/emacs-27
+cd ~/emacs/emacs-28
 git cherry-pick -xe 958b768a6534ae6e77a8547a56fc31b46b63710b
 
 and add "Backport:" to the commit string.  Then
@@ -109,7 +109,7 @@ up-to-date by doing a pull.  Then start Emacs with
   emacs -l admin/gitmerge.el -f gitmerge
 
 You'll be asked for the branch to merge, which will default to
-(eg) 'origin/emacs-27', which you should accept.  Merging a local tracking
+(eg) 'origin/emacs-28', which you should accept.  Merging a local tracking
 branch is discouraged, since it might not be up-to-date, or worse,
 contain commits from you which are not yet pushed upstream.