Update gem version in NEWS [ci skip]

ref 77d7ac7

Author: znz

NEWS.md

@@ -143,7 +143,7 @@ The following bundled gems are updated.
 * test-unit 3.6.1
 * rexml 3.2.6
 * rss 0.3.0
-* net-imap 0.4.1
+* net-imap 0.4.2
 * net-smtp 0.4.0
 * rbs 3.2.2
 * typeprof 0.21.8