fix(cargo): we need >=GTK+3-3.20
Glade warns that some of the features we use for GtkModelButton
needs GTK+3>=3.20
@@ -19,8 +19,8 @@ gio = "0.5"
glib = "0.6"
glib-sys = { version = "0.7", features = ["v2_36"] }
gobject-sys = "0.7"
-gtk = { version = "0.5", features = ["v3_18"] }
-gtk-sys = { version = "0.7", features = ["v3_18"] }
+gtk = { version = "0.5", features = ["v3_20"] }
+gtk-sys = { version = "0.7", features = ["v3_20"] }
lazy_static = "1"
libc = "0.2"
log = "0.4"
