"sudo apt update" failure in linux

Environments Linux
3

The MySQL repository is broken upstream. See Can't install MySQL 5.7 on Ubuntu Trusty.

If it helps, you’ll be able to use MySQL 5.7 on our Xenial image. To do so, please remove

addons:
  apt:
    sources:
      - mysql-5.7-trusty
    packages:
      - mysql-server

and add

dist: xenial
services:
  - redis-server
  - mysql

to your .travis.yml file.

Please let us know how it goes.

Thanks!