[gimp] README: s/2.9/2.10/ and make it say "stable"

[Michael Natterer <mitch src gnome org>]

commit 3c410273b0b65d4503e1f88e4e85ba34835d4b3a
Author: Michael Natterer <mitch gimp org>
Date:   Thu Apr 26 16:07:00 2018 +0200

    README: s/2.9/2.10/ and make it say "stable"

 README |   19 ++++++++-----------
 1 files changed, 8 insertions(+), 11 deletions(-)
---
diff --git a/README b/README
index d3a13f6..6d8931e 100644
--- a/README
+++ b/README
@@ -1,16 +1,13 @@
                    ------------------------------
                    GNU Image Manipulation Program
-                       2.9 Development Branch
+                         2.10 Stable Branch
                    ------------------------------
 
-This is an unstable development release, an intermediate state on the
-way to the next stable release 2.10. GIMP 2.9 may or may not do what
-you expect. Save your work early and often. If you want a stable
-version, please use GIMP 2.8 instead.
+This is a stable release in the GIMP 2.10 series.
 
-GIMP 2.9 replaces earlier GIMP 2.x versions. It is advised that you
-uninstall them before installing GIMP 2.9. If you want to keep your
-older GIMP 2.x installation in parallel to GIMP 2.9, you have to
+GIMP 2.10 replaces earlier GIMP 2.x versions. It is advised that you
+uninstall them before installing GIMP 2.10. If you want to keep your
+older GIMP 2.x installation in parallel to GIMP 2.10, you have to
 choose a separate prefix which is not in your default library search
 path. Otherwise your previous GIMP installation will start to use the
 new libraries. You have been warned.
@@ -85,12 +82,12 @@ The look of GIMP's interface can be customized like any other GTK app
 by editing the ~/.gtkrc-2.0 file or by using "themes" (ready-made
 customizations).  For downloadable themes and further details, see
 http://art.gnome.org/themes/gtk2 . Additionally, GIMP reads the file
-~/.config/GIMP/2.9/gtkrc so you can have settings that only apply to GIMP.
+~/.config/GIMP/2.10/gtkrc so you can have settings that only apply to GIMP.
 
 Included is a set of keybindings similar to those in Adobe Photoshop.
 You can find them in the ps-menurc file.  To use them, copy this file
-to ~/.config/GIMP/2.9/menurc. You can also manually change the keybindings to
-any of your choice by editing ~/.config/GIMP/2.9/menurc.
+to ~/.config/GIMP/2.10/menurc. You can also manually change the keybindings
+to any of your choice by editing ~/.config/GIMP/2.10/menurc.
 
 
 Have fun,