Bump net-imap from 0.5.1 to 0.5.6 (#2937)

Bumps [net-imap](https://github.com/ruby/net-imap) from 0.5.1 to 0.5.6.
- [Release notes](https://github.com/ruby/net-imap/releases)
- [Commits](https://github.com/ruby/net-imap/compare/v0.5.1...v0.5.6)

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

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

Gemfile.lock

@@ -278,7 +278,7 @@ GEM
     nested_form (0.3.2)
     net-http (0.4.1)
       uri
-    net-imap (0.5.1)
+    net-imap (0.5.6)
       date
       net-protocol
     net-pop (0.1.2)
@@ -494,7 +494,7 @@ GEM
     thor (1.3.2)
     thread_safe (0.3.6)
     timecop (0.9.8)
-    timeout (0.4.2)
+    timeout (0.4.3)
     turbo-rails (2.0.11)
       actionpack (>= 6.0.0)
       railties (>= 6.0.0)