Trivial Description
npm install reports a warning
npm WARN tsutils@3.17.1 requires a peer of typescript@>=2.8.0 || >= 3.2.0-dev || >= 3.3.0-dev || >= 3.4.0-dev || >= 3.5.0-dev || >= 3.6.0-dev || >= 3.6.0-beta || >= 3.7.0-dev || >= 3.7.0-beta but none is installed. You must install peer dependencies yourself.
This is relevant because eslint will not run without typescript. The GitHub Action has to install typescript in a subsequent step.
Adding typescript would also allow to write production code and/or tests in typescript, which has some advantages. The Patternfly project seems especially to be very Typescript focused, recently. The Rhea AMQP client also added typescript type annotations.