docker ubuntu 18.04 installation: tzdata configuration

Setting up tzdata (2018d-1) ...
debconf: unable to initialize frontend: Dialog
debconf: (No usable dialog-like program is installed, so the dialog based frontend cannot be used. at /usr/share/perl5/Debconf/FrontEnd/Dialog.pm line 76.)
debconf: falling back to frontend: Readline
Configuring tzdata
------------------

Please select the geographic area in which you live. Subsequent configuration
questions will narrow this down by presenting a list of cities, representing
the time zones in which they are located.

  1. Africa      4. Australia  7. Atlantic  10. Pacific  13. Etc
  2. America     5. Arctic     8. Europe    11. SystemV
  3. Antarctica  6. Asia       9. Indian    12. US
Geographic area: 8

+++ docker/web-build/Dockerfile
@@ -1,9 +1,10 @@
-FROM ubuntu:16.04
+FROM ubuntu:18.04
 
 MAINTAINER "Christian Weiske" <weiske@mogic.com>
 
 ENV TERM=xterm\
-    TZ=Europe/Berlin
+    TZ=Europe/Berlin\
+    DEBIAN_FRONTEND=noninteractive