[gspell] readme: document that gspell uses the same versioning scheme as GNOME

[Sébastien Wilmet <swilmet src gnome org>]

commit 096fc29976d908f42bce83cf7d2ae48cc9f4ab44
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Mon Jul 17 11:57:30 2017 +0200

    readme: document that gspell uses the same versioning scheme as GNOME

 README |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/README b/README
index e5ca51a..7d22515 100644
--- a/README
+++ b/README
@@ -15,7 +15,9 @@ The official web site is:
 About versions
 --------------
 
-gspell follows the GNOME release schedule.
+gspell follows the GNOME release schedule and uses the same versioning scheme:
+
+    https://developer.gnome.org/programming-guidelines/stable/versioning.html.en
 
 gspell 0.1.x should be installed alongside GNOME 3.18.
 gspell 1.0.x should be installed alongside GNOME 3.20.