[niepce] Add gexiv2 requirement in README

[Hubert Figuière <hub src gnome org>]

commit 1504e05ac29f7dfcccfc5666926961d11366d579
Author: Hubert Figuière <hub figuiere net>
Date:   Sun Nov 25 10:59:01 2018 -0500

    Add gexiv2 requirement in README

 README | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/README b/README
index 0a97ce7..3ea5e8c 100644
--- a/README
+++ b/README
@@ -40,6 +40,7 @@ libopenraw >= 0.1.0
 gegl >= 0.3.0
 babl
 libgphoto2
+gexiv2 >= 0.10 (as required by rexiv2)
 
 Niepce is being developed on Linux. It should build and work on other
 UNIX systems.
@@ -68,4 +69,4 @@ IRC
 Mailing list
 ------------
 
-https://mail.gna.org/listinfo/niepce-devel/
+https://mail.gna.org/listinfo/niepce-devel/
\ No newline at end of file