[libglnx] README.md: Change xdg-app to flatpak

[Matthew Leeds <mwleeds src gnome org>]

commit 210bcfcb65eb50ffef9cb541424dbd3b9b84997e
Author: Matthew Leeds <matthew leeds endlessm com>
Date:   Thu Jul 13 15:43:48 2017 -0700

    README.md: Change xdg-app to flatpak

 README.md |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/README.md b/README.md
index 241f5ce..8fb2faa 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ Why?
 ----
 
 There are multiple projects which have a hard dependency on Linux and
-GLib, such as NetworkManager, ostree, xdg-app, etc.  It makes sense
+GLib, such as NetworkManager, ostree, flatpak, etc.  It makes sense
 for them to be able to share Linux-specific APIs.
 
 This module also contains some code taken from systemd, which has very