Travis: update to 20.04

0xc0170 · 0xc0170 · commit 5057bfd9bdd0 · 2021-04-15T13:34:31.000+01:00
Updating to the latest Travis provided environment. It's been a year around and we can benefit from more updated versions we use. More info https://docs.travis-ci.com/user/reference/focal/
diff --git a/.travis.yml b/.travis.yml
@@ -16,7 +16,7 @@
 
 language: sh
 os: linux
-dist: xenial
+dist: focal
 
 
 env:
