If your YAML build definition invokes rvm (Ruby Version Manager), you will run into errors. To work around the issue, you need to switch your build to using rbenv instead. Rbenv is a lightweight and more developer-friendly option to switch between Ruby versions.
To continue using different versions of Ruby, replace any instances of rvm in your YAML build definition with equivalent rbenv commands.
rvm install x.x.x becomes rbenv install x.x.x.
rvm use x.x.x becomes rbenv global x.x.x or rbenv local x.x.x depending on the desired behavior.
Why cannot I use RVM? | Acquia Product Documentation
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