DEV: update mini_racer for ARM support (#12682)

DEV: update mini_racer for ARM support (#12682)

New version of mini_racer support M1 and ARM builds of Ruby

This should make developing on Discourse easier

Co-authored-by: Robin Ward robin.ward@gmail.com


GitHub sha: 71475a1a

This commit appears in #12682 which was approved by CvX. It was merged by eviltrout.