[Fix #8165] Require Parser gem 2.7.1.5
[Fix #8165] Require Parser gem 2.7.1.5

Parser 2.7.1.5 includes https://github.com/whitequark/parser/pull/717
and fixes #8165.

tdeo/rubocop,tdeo/rubocop,bbatsov/rubocop,rrosenblum/rubocop,rrosenblum/rubocop,maxjacobson/rubocop,maxjacobson/rubocop,rrosenblum/rubocop,maxjacobson/rubocop,tejasbubane/rubocop,bbatsov/rubocop,tdeo/rubocop,tejasbubane/rubocop,tejasbubane/rubocop