As noted in #910, we have invalid configuration shared as an example,
which isn't ideal.
We should validate any JSON and `config.js` files in the example
directory.
We need to make sure that we override the ESM settings in this repo, as
otherwise we receive:
module is not defined in ES module scope
When trying to validate the `renovate-config.js`.
This also follows the usage of a container from Renovate[0] for using
the container to run the validator.
[0]: 2ab0f77818/.github/workflows/test.yml (L44)
