Bump net-imap from 0.5.3 to 0.5.4 (#2859)

Bumps [net-imap](https://github.com/ruby/net-imap) from 0.5.3 to 0.5.4.
- [Release notes](https://github.com/ruby/net-imap/releases)
- [Commits](ruby/net-imap@v0.5.3...v0.5.4)

---
updated-dependencies:
- dependency-name: net-imap
  dependency-type: indirect
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -163,7 +163,7 @@ GEM
     minitest (5.25.4)
     msgpack (1.7.5)
     mutex_m (0.3.0)
-    net-imap (0.5.3)
+    net-imap (0.5.4)
       date
       net-protocol
     net-pop (0.1.2)