All mailing list URL

CONTRIBUTING.md

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 5a02c44..e37802a 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -60,4 +60,4 @@
 
 Contact the project developers via the project's "dev" list.
 
-* 
+* https://accounts.eclipse.org/mailing-list/el-dev