How to provision a server with php7.1 now that Trellis is updated to php7.2

I have a requirement here where I need to use php7.1 and I would like Ansible to manage this for me as normal… there were posts about how to install 7.2 when Trellis wasn’t yet 7.2 ready, but I don’t see anything about using 7.1 using today’s version of Trellis

Would really appreciate some guidance with this… thanks