build: explicitely set the OS in travis
commitfa8a13b3b7bff61eae783b4f22dfc7b14ad1e24a
authorNicola Fontana <ntd@entidi.it>
Tue, 27 Apr 2021 06:09:14 +0000 (27 08:09 +0200)
committerNicola Fontana <ntd@entidi.it>
Tue, 27 Apr 2021 06:13:30 +0000 (27 08:13 +0200)
tree3a1d12ebc0df64230a7195299809c36a63936879
parent189be49801a71a272a8bd869f13579989cf4df0a
build: explicitely set the OS in travis

The YAML eavily relies on Xenial Ubuntu, so enforce it to avoid future
surprises (will be EOL this month).
.travis.yml