Travis build failing (bundler requires Ruby version >= 3)

[lrytz]

0.01s$ ruby -v
ruby 2.7.6p219 (2022-04-12 revision c9c2245c0a) [x86_64-linux]
16.34s$ gem install bundler
Fetching bundler-2.5.1.gem
ERROR:  Error installing bundler:
	The last version of bundler (>= 0) to support your Ruby & RubyGems was 2.4.22. Try installing it with `gem install bundler -v 2.4.22`
	bundler requires Ruby version >= 3.0.0. The current ruby version is 2.7.6.219.
The command "gem install bundler" failed and exited with 1 during .

on recent PRs. Similarly, scala/scala3#19286 (rubygems-update instead of bundler).