Merge pull request #621 from ruby/dependabot/bundler/net-imap-0.6.4

Bump net-imap from 0.6.3 to 0.6.4

Author: hsbt

Gemfile.lock

@@ -169,7 +169,7 @@ GEM
       drb (~> 2.0)
       prism (~> 1.5)
     msgpack (1.8.0)
-    net-imap (0.6.3)
+    net-imap (0.6.4)
       date
       net-protocol
     net-pop (0.1.2)