Mule App GitHub Actions Setup

I have a MuleSoft project living in a private GitHub repository and I want the Build stage fully automated with GitHub Actions. At the moment there is a workflow file which is a YAML that kicks in on every push or pull-request to the main and develop branches, spins up a suitable Java runner, fetches the Mule Maven plugin.

But it gives error when it tries to resolve dependencies and produce a versioned deployable artefact (the packaged .jar).

The error is because it tries to look for dependencies in central repository. I want it to look at a custom repository instead.

This should be a simple work for someone who knows this.