Move Travis to Ubuntu Bionic 18.04

Description

Bionic is closer to the production environment (Debian 10).

https://docs.travis-ci.com/user/reference/bionic

Environment

None

Status

Assignee

redsummernight

Reporter

redsummernight

Roadmap

Misc

Priority

Low

Affects versions

Fix versions

Components

AutomatedTests

Difficulty

Easy

Required Access Level

None

Milestone

Internal 0.9
Configure