multimail: stop shipping a copy

The multimail project is developed independently and has its own project
page. Traditionally, we shipped a copy in contrib/.

However, such a copy is prone to become stale, and users are much better
served to be directed to the actual project instead.

Signed-off-by: Johannes Schindelin <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: dscho

contrib/hooks/multimail/CHANGES

@@ -1,15 +1,7 @@
-This copy of git-multimail is distributed as part of the "contrib"
-section of the Git project as a convenience to Git users.
 git-multimail is developed as an independent project at the following
 website:
 
     https://github.com/git-multimail/git-multimail
 
-The version in this directory was obtained from the upstream project
-on January 07 2019 and consists of the "git-multimail" subdirectory from
-revision
-
-    04e80e6c40be465cc62b6c246f0fcb8fd2cfd454 refs/tags/1.5.0
-
-Please see the README file in this directory for information about how
-to report bugs or contribute to git-multimail.
+Please refer to that project page for information about how to report
+bugs or contribute to git-multimail.