Context: https://twitter.com/peter_szilagyi/status/1437646118700175360
Apparently, travis-ci have ultimately decided they don’t want any customers anymore.
As long as you’re not using private credentials, running builds on travis-ci is probably still fine, although not recommended. It would be a good idea to switch to a more responsible alternative.
If you have private credentials in travis-ci, you should immediately cycle them and move away from travis-ci.