v15.0.0

Bump version to 15.0.0 for those who don't use custom .lints.json.

Breaking changes (for those who don't use custom .lints.json):

• Add dockerfilelint

Fixes:

• Add support for YAML in linter configs

Other changes:

• Update dependencies

If you already have a .lints.json, in order to use dockerfilelint you need to add it to your .lints.json, as in src/default.lints.json.

If you wish to customize dockerfilelint rules you can create a .dockerfilelintrc file in the root of your project (see more about it at https://github.com/replicatedhq/dockerfilelint#configuring).