upgrade discourse-virtmail plugin

Author: mortbauer

Dockerfile

@@ -83,7 +83,7 @@ ENV DISCOURSE_CHECKLIST_VERSION=6fcf9fed5c3ae3baf9ddd1cca9cef4dc089996c1
 ENV DISCOURSE_SOLVED_VERSION=f7bbffa6173b6e06a232e2eeaaef1e4da2d9cb8c
 ENV DISCOURSE_GROUP_GLOBAL_NOTICE_VERSION=598c3f22d000d9eb11df073f8e8d749797624653
 ENV DISCOURSE_MULTI_SSO_VERSION=e19fc0a860613a10dfc1e080484e3f2e76009da8
-ENV DISCOURSE_VIRTMAIL_VERSION=0ac3f3fc1bb07cdc72c2db9c6505a9241ad4e805
+ENV DISCOURSE_VIRTMAIL_VERSION=5b732d61309560ab66e6696c5165c49a8aa9c431
 
 RUN cd plugins \
     && curl -L https://github.com/discourse/discourse-assign/archive/${DISCOURSE_ASSIGN_VERSION}.tar.gz | tar -xz \