[gimp] INSTALL: update mypaint-brushes repository (finally upstream!).

[Jehan <jehanp src gnome org>]

commit 5ac267820f3120acf0dc8ce78240a8a7b220e270
Author: Jehan <jehan girinstud io>
Date:   Sun Sep 30 20:44:38 2018 +0200

    INSTALL: update mypaint-brushes repository (finally upstream!).
    
    The MyPaint project now hosts the repository which was under my name
    previously. Yeah!

 INSTALL.in | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/INSTALL.in b/INSTALL.in
index 93cf39e526..87b4606d66 100644
--- a/INSTALL.in
+++ b/INSTALL.in
@@ -86,10 +86,9 @@ header files installed.
      Checkout the tag "v1.3.0" instead, or simply install from a tarball
      or from your favorite package manager.
 
- 11. We also need the mypaint-brushes data package with is currently
-     hosted by Jehan, until the MyPaint project takes care of it:
+ 11. We also need the mypaint-brushes data package:
 
-        https://github.com/Jehan/mypaint-brushes
+        https://github.com/mypaint/mypaint-brushes
 
      If installing from repository, install from branch "v1.3.x" or the
      particular tag "v1.3.0". In particular do not install from master