OPT: Bump net-imap from 0.5.4 to 0.5.6 in the bundler group

Bumps the bundler group with 1 update: [net-imap](https://github.com/ruby/net-imap).


Updates `net-imap` from 0.5.4 to 0.5.6
- [Release notes](https://github.com/ruby/net-imap/releases)
- [Commits](ruby/net-imap@v0.5.4...v0.5.6)

---
updated-dependencies:
- dependency-name: net-imap
  dependency-type: indirect
  dependency-group: bundler
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -187,7 +187,7 @@ GEM
     mini_portile2 (2.8.8)
     minitest (5.25.4)
     msgpack (1.7.3)
-    net-imap (0.5.4)
+    net-imap (0.5.6)
       date
       net-protocol
     net-pop (0.1.2)