git subrepo pull (merge) mailcow/src/mailcow-dockerized

Among other things, this updates Dovecot to 2.3.13, which is a
critical security update.

subrepo: subdir:   "mailcow/src/mailcow-dockerized"
  merged:   "376574d9"
upstream: origin:   "https://github.com/mailcow/mailcow-dockerized.git"
  branch:   "master"
  commit:   "6f14955b"
git-subrepo: version:  "0.4.3"
  origin:   "???"
  commit:   "???"
Change-Id: Idf4859ddaaebf6997afbb0cebffc8bf3f5b902a0
diff --git a/mailcow/src/mailcow-dockerized/data/Dockerfiles/dovecot/Dockerfile b/mailcow/src/mailcow-dockerized/data/Dockerfiles/dovecot/Dockerfile
index 691f9a7..219dd14 100644
--- a/mailcow/src/mailcow-dockerized/data/Dockerfiles/dovecot/Dockerfile
+++ b/mailcow/src/mailcow-dockerized/data/Dockerfiles/dovecot/Dockerfile
@@ -2,7 +2,7 @@
 LABEL maintainer "Andre Peters <andre.peters@servercow.de>"
 
 ARG DEBIAN_FRONTEND=noninteractive
-ARG DOVECOT=2.3.11.3
+ARG DOVECOT=2.3.13
 ENV LC_ALL C
 
 # Add groups and users before installing Dovecot to not break compatibility