Bump net-imap from 0.5.0 to 0.5.6 (#1444)

Bumps [net-imap](https://github.com/ruby/net-imap) from 0.5.0 to 0.5.6.
- [Release notes](https://github.com/ruby/net-imap/releases)
- [Commits](ruby/net-imap@v0.5.0...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

@@ -145,7 +145,7 @@ GEM
       qonfig (>= 0.24)
     dalli (3.2.8)
     database_cleaner (1.7.0)
-    date (3.4.0)
+    date (3.4.1)
     derailed_benchmarks (2.2.1)
       base64
       benchmark-ips (~> 2)
@@ -272,7 +272,7 @@ GEM
     msgpack (1.7.3)
     mutex_m (0.2.0)
     nenv (0.3.0)
-    net-imap (0.5.0)
+    net-imap (0.5.6)
       date
       net-protocol
     net-pop (0.1.2)
@@ -432,7 +432,7 @@ GEM
     stackprof (0.2.26)
     thor (1.3.2)
     tilt (2.4.0)
-    timeout (0.4.1)
+    timeout (0.4.3)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
     uglifier (4.2.1)