* master: (60 commits)
  Added tslint-brunch to the list of 3rd party tools (palantir#4251)
  Switch to tslint-plugin-prettier, clean up rule options config syntax (palantir#4488)
  Enable grouped-imports for ordered-imports rule in tslint:all config (palantir#4420)
  Ordered imports grouping (palantir#4134)
  trailing-comma: check for a closing parenthesis (palantir#4457)
  Update index.md (palantir#4473)
  [bugfix] `no-unsafe-any`: allow implicitly downcasting `any` to `unknown` (palantir#4442)
  Add v5.12.1 changelog
  Bump version to 5.12.1
  Fix quotemark avoid-template issues (palantir#4408)
  Skip linting JSON files entirely (palantir#4001)
  Fix strict-type-predicate for unknown (palantir#4444)
  restrict increment-decrement fixer while fixing the postfix unary expressions (palantir#4415)
  Mention file names in script parse failures (palantir#4397)
  Revert breaking change to tslint:recommended, update tslint:latest (palantir#4404)
  Fix quotemark avoid-template issues (palantir#4408)
  Bump tslint dev dependency to 5.12.0 (palantir#4452)
  Skip linting JSON files entirely (palantir#4001)
  Fix strict-type-predicate for unknown (palantir#4444)
  [README] Update link for Webstorm (palantir#4450)
  ...