Auto merge of #4990 - bundler:seg-realworld-flex, r=segiddins
Auto merge of #4990 - bundler:seg-realworld-flex, r=segiddins

Dynamically fetch expected rails version

This way, we don't have to update this expectation every time a new rails version comes out

bundler/bundler,dilumnavanjana/bundler,bundler/bundler,dilumnavanjana/bundler,mvz/bundler,mvz/bundler