Switch TravisCI to Ubuntu 20.04

534de867 · Moritz Grimm · d041a54f · 534de867
Commit 534de867 authored Feb 11, 2021 by Moritz Grimm
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@ env:
 compiler:
  - gcc

-dist: trusty
+dist: focal
 sudo: required
 addons:
  apt: