Bump net-imap from 0.4.15 to 0.4.19

Bumps [net-imap](https://github.com/ruby/net-imap) from 0.4.15 to 0.4.19.
- [Release notes](https://github.com/ruby/net-imap/releases)
- [Commits](ruby/net-imap@v0.4.15...v0.4.19)

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -90,7 +90,7 @@ GEM
       xpath (~> 3.2)
     concurrent-ruby (1.3.4)
     crass (1.0.6)
-    date (3.3.4)
+    date (3.4.1)
     debug (1.9.2)
       irb (~> 1.10)
       reline (>= 0.3.8)
@@ -156,7 +156,7 @@ GEM
       ruby2_keywords (~> 0.0.1)
     mustermann-grape (1.1.0)
       mustermann (>= 1.0.0)
-    net-imap (0.4.15)
+    net-imap (0.4.19)
       date
       net-protocol
     net-pop (0.1.2)
@@ -296,7 +296,7 @@ GEM
       railties (>= 6.0.0)
     stringio (3.1.1)
     thor (1.3.2)
-    timeout (0.4.1)
+    timeout (0.4.3)
     turbo-rails (2.0.6)
       actionpack (>= 6.0.0)
       activejob (>= 6.0.0)