mix excessibility.install (Excessibility v0.5.13)

Installs Excessibility into a host project using Igniter.

This task can be invoked directly or via mix igniter.install excessibility. It adds the recommended configuration to the target project's config/test.exs and (by default) runs npm install inside the vendored Excessibility assets directory to fetch Pa11y.

Requires Igniter to be installed in the host project.