Upgrade from trusty to focal

jmatsushita · jmatsushita · commit f43fb808706d · 2021-07-15T21:47:14.000+02:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,4 +1,4 @@
-dist: trusty
+dist: focal
 sudo: required
 language: node_js
 node_js:
