Building master KDE PIM with Docker

[David Jarvie]

I have followed the instructions at https://community.kde.org/KDE_PIM/Docker 
for building kdepim, but the Neon image (based on Ubuntu Xenial 16.04) is too 
old to provide the necessary dependencies. For example, it only provides 
libical 1.0, whereas master kdepim requires libical 2.0.

Is there a way to update Neon in the Docker container, to allow kdepim master 
to be built?

-- 
David Jarvie.
KDE developer.
KAlarm author -- http://www.astrojar.org.uk/kalarm