Drop Python 3.5 support and bump other dependencies
Motivated by the EOL of Python 3.5 and the EOL of Ubuntu 16.04 next year this requires Python 3.6 and moves all other dependencies to what is available in Ubuntu 18.04.
Motivated by the EOL of Python 3.5 and the EOL of Ubuntu 16.04 next year this requires Python 3.6 and moves all other dependencies to what is available in Ubuntu 18.04.