[gitg] #227 fix CSS warning on MacOS

[Alberto Fanjul <albfan src gnome org>]

commit acdf310fbbdc3e9c86d88c0b4ce0994449e610b5
Author: Erez Volk <erez volk gmail com>
Date:   Fri Apr 24 08:31:57 2020 +0300

    #227 fix CSS warning on MacOS

 gitg/resources/ui/style-osx.css | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gitg/resources/ui/style-osx.css b/gitg/resources/ui/style-osx.css
index 9a0adcfb..cd43ee01 100644
--- a/gitg/resources/ui/style-osx.css
+++ b/gitg/resources/ui/style-osx.css
@@ -1,5 +1,5 @@
 /* osx css styles */
 
 .monospace {
-       font: menlo;
+       font-family: menlo;
 }