build(deps): bump net-imap from 0.5.4 to 0.5.6 (#775)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -236,7 +236,7 @@ GEM
     mini_mime (1.1.5)
     minitest (5.25.4)
     msgpack (1.7.5)
-    net-imap (0.5.4)
+    net-imap (0.5.6)
       date
       net-protocol
     net-pop (0.1.2)