remove mirrors-prettier

Author: asottile

all-repos.yaml

@@ -6,7 +6,6 @@
 - https://github.com/pre-commit/mirrors-fixmyjs
 - https://github.com/pre-commit/mirrors-jshint
 - https://github.com/pre-commit/mirrors-mypy
-- https://github.com/pre-commit/mirrors-prettier
 - https://github.com/pre-commit/mirrors-puppet-lint
 - https://github.com/pre-commit/mirrors-scss-lint
 - https://github.com/pre-commit/mirrors-yapf