docker-src image building quits with error using apt

[metas-jb]

Issue:
When building the images for app or webapi directly from metasfresh/docker-src/ the build process aborts with following message:

...
Err:29 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 postgresql-client-9.5 amd64 9.5.7-0ubuntu0.16.04 404  Not Found [IP: 91.189.88.149 80]
Fetched 6844 kB in 0s (22.0 MB/s)
E: Failed to fetch http://archive.ubuntu.com/ubuntu/pool/main/p/postgresql-9.5/libpq5_9.5.7-0ubuntu0.16.04_amd64.deb  404  Not Found [IP: 91.189.88.149 80]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/pool/main/p/postgresql-9.5/postgresql-client-9.5_9.5.7-0ubuntu0.16.04_amd64.deb  404  Not Found [IP: 91.189.88.149 80]
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
Service 'app' failed to build: The command '/bin/sh -c apt -y install netcat     && apt -y install curl     && apt -y install openjdk-8-jdk-headless     && apt -y install postgresql-client-9.5     && apt -y autoremove     && apt -y autoclean' returned a non-zero code: 100