Build(deps): Bump net-imap from 0.5.5 to 0.5.6 (#31250)

Bumps [net-imap](https://github.com/ruby/net-imap) from 0.5.5 to 0.5.6.
- [Release notes](https://github.com/ruby/net-imap/releases)
- [Commits](https://github.com/ruby/net-imap/compare/v0.5.5...v0.5.6)

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

Gemfile.lock

@@ -265,7 +265,7 @@ GEM
     mustache (1.1.1)
     net-http (0.6.0)
       uri
-    net-imap (0.5.5)
+    net-imap (0.5.6)
       date
       net-protocol
     net-pop (0.1.2)