Update bundled gems list at 8c4e52f [ci skip]

Author: matzbot

NEWS.md

@@ -213,7 +213,9 @@ Note: We're only listing outstanding class updates.
     * timeout 0.3.0
 *   The following bundled gems are updated.
     * minitest 5.16.3
-    * net-imap 0.2.3
+    * net-imap 0.3.0
+    * net-pop 0.1.2
+    * net-smtp 0.3.2
     * rbs 2.6.0
     * typeprof 0.21.3
     * debug 1.6.2