Update synapse to 1.19.2

Dockerfile

@@ -4,7 +4,7 @@ RUN mkdir -p /app/pkg
 
 WORKDIR /app/code
 
-ARG VERSION=v1.19.1
+ARG VERSION=v1.19.2
 
 # https://pythonspeed.com/articles/activate-virtualenv-dockerfile/
 RUN virtualenv -p python3 /app/code/env

POSTINSTALL.md

@@ -1,5 +1,5 @@
 Account ids are created with the username and the second level domain under which the
-app is installed e.g. `@username@domain.com`.
+app is installed e.g. `@$CLOUDRON-USERNAME@$CLOUDRON-APP-DOMAIN`.
 
 For federation to work, the second level domain has to be configured to serve up the
 `.well-known/domain.com/matrix` URI. See the