Bump net-imap from 0.5.1 to 0.5.2

Bumps [net-imap](https://github.com/ruby/net-imap) from 0.5.1 to 0.5.2.
- [Release notes](https://github.com/ruby/net-imap/releases)
- [Commits](ruby/net-imap@v0.5.1...v0.5.2)

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

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -186,7 +186,7 @@ GEM
       activerecord (>= 5.a)
       database_cleaner-core (~> 2.0.0)
     database_cleaner-core (2.0.1)
-    date (3.4.0)
+    date (3.4.1)
     defra_ruby_alert (2.2.1)
       airbrake
     defra_ruby_style (0.4.0)
@@ -312,7 +312,7 @@ GEM
     multi_json (1.15.0)
     net-http (0.4.1)
       uri
-    net-imap (0.5.1)
+    net-imap (0.5.2)
       date
       net-protocol
     net-pop (0.1.2)
@@ -506,7 +506,7 @@ GEM
       concurrent-ruby (~> 1.0)
     thor (1.3.2)
     tilt (2.3.0)
-    timeout (0.4.2)
+    timeout (0.4.3)
     timers (4.3.5)
     traces (0.11.1)
     turbolinks (5.2.1)