Merge pull request #340 from cbarrete/vcard

Add vCard source to the README

Author: vigoux

README.md

@@ -75,6 +75,7 @@ another completion source instead(Ex: snippets).
     * [completion-tabnine](https://github.com/aca/completion-tabnine): AI code completion tool TabNine integration.
     * [completion-tags](https://github.com/kristijanhusak/completion-tags): Slightly improved ctags completion
     * [completion-tmux](https://github.com/albertoCaroM/completion-tmux): tmux panels completion
+    * [completion-vcard](https://github.com/cbarrete/completion-vcard): email completion from vCards
 
 ## Configuration