Unfortunately, I found no way to get the APT addon working following the documentation for Bionic. In my case running apt update directly does not seem to trigger the execution of the APT addon either.
Same issue here…
I’ve been struggling with this for a few days before I actually realized what was the issue, since it’s not documented anywhere…
Any idea about when travis-ci/travis-build#1754 will be merged? If it’s not soon, perhaps it could be worth mentioning it somewhere on bionic documentation.