[gnome-builder] Update CONTRIBUTING.md

[Christian Hergert <chergert src gnome org>]

commit 6cc77d57e5b65a7d982e12b9c3da51c51b5f37e5
Author: Ayush das <ayush24das gmail com>
Date:   Mon Mar 22 16:30:32 2021 +0530

    Update CONTRIBUTING.md

 CONTRIBUTING.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 546143bb4..4105c81c0 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -43,8 +43,8 @@ We run these tests often so it is important that you check nothing was broken by
 
 ## Licensing
 
-Contributions should be licensed under the LGPL-2.1+ or GPL-3.
-Permissively licensed contributions will also be accepted, but we prefer that original contributions are 
either LGPL-2.1+ or GPL-3 licensed.
+Contributions should be licensed under the **LGPL-2.1+** or **GPL-3**. 
+Permissively licensed contributions will also be accepted, but we prefer that original contributions are 
either **LGPL-2.1+** or **GPL-3** licensed.
 
 ## Coding Style