Add @bitdancer as codeowner of email related stuff. (GH-2987)

diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
index 137681b..1c5164f 100644
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -19,3 +19,10 @@
 
 # SSL
 **/*ssl*                      @tiran
+
+# Email and related
+**/*mail*                     @bitdancer
+**/*smtp*                     @bitdancer
+**/*mime*                     @bitdancer
+**/*imap*                     @bitdancer
+**/*poplib*                   @bitdancer