[glibmm] Mark the branch in the ChangeLog

[Murray Cumming <murrayc src gnome org>]

commit dfd720d612abc216c09308ab820cb7896189e1b1
Author: Murray Cumming <murrayc murrayc com>
Date:   Mon Apr 1 18:09:54 2013 +0200

    Mark the branch in the ChangeLog

 ChangeLog |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 9b36c3b..75945fd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+This is the master branch for glibmm 3.7/8.
+See also the glibmm-3-6 branch.
+
 2013-03-31  José Alburquerque  <jaalburquerque gmail com>
 
        TlsCertificate: Use std::string for data instead of char*.