[evince] Fix logo in README and add flatpak button

[Germán Poo-Caamaño <gpoo src gnome org>]

commit 59bb19fdfb0dddd52ae809aa133187f39456c102
Author: Roger <sachanroger gmail com>
Date:   Mon Sep 30 20:07:05 2019 +0000

    Fix logo in README and add flatpak button

 README.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/README.md b/README.md
index 23439abe..6c13a933 100644
--- a/README.md
+++ b/README.md
@@ -7,6 +7,8 @@ https://wiki.gnome.org/Apps/Evince.
 
 This software is licensed under the [GPLv2][license].
 
+[![flatpak]](https://flathub.org/apps/details/org.gnome.Evince)
+
 ## Evince Requirements
 
 * [GNOME Platform libraries][gnome]
@@ -30,4 +32,5 @@ This software is licensed under the [GPLv2][license].
 [tiff]: http://libtiff.org/
 [xps]: https://wiki.gnome.org/Projects/libgxps
 [license]: COPYING
-[evince-logo]: data/icons/48x48/apps/org.gnome.Evince.png
+[evince-logo]: data/icons/scalable/apps/org.gnome.Evince.svg
+[flatpak]: 
https://upload.wikimedia.org/wikipedia/commons/thumb/a/a6/Flathub-badge-en.svg/240px-Flathub-badge-en.svg.png
\ No newline at end of file