[librsvg/librsvg-2.42] Remind people that github will delete their pull requests

[Federico Mena Quintero <federico src gnome org>]

commit 986a95ebdcdbbdbfea558dcecdae3aec5cf5ff79
Author: Federico Mena Quintero <federico gnome org>
Date:   Fri Jun 1 19:33:31 2018 -0500

    Remind people that github will delete their pull requests

 README.md | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/README.md b/README.md
index 08fa2dc4..058d07b9 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,10 @@ generate output for printing.
 Do you want to render non-animated SVGs to a Cairo surface with a
 minimal API?  Librsvg may be adequate for you.
 
+***GITHUB WILL DELETE YOUR PULL REQUESTS*** We use
+[`gitlab.gnome.org`](https://gitlab.gnome.org/GNOME/librsvg) instead.
+Please see [`CONTRIBUTING.md`][contributing] for details.
+
 Using librsvg
 -------------