CI: Bump lint stage to elixir-1.12

Elixir 1.12 changed formatting rules, this allows to avoid having to rollback to run `mix format`
3 jobs for ci/bump-elixir-lint
Status Job ID Name Coverage
  Benchmark
manual #196781
allowed to fail manual
benchmark
 
  Deploy
manual #196782
allowed to fail manual
review_app
manual #196783
allowed to fail manual
stop_review_app