Configure reporter from the environment

[nijel]

Presently, it is possible to configure reporter on the command line only. I'd like to be able to configure this using an environment variable as well.

We use biome in pre-commit. When this is triggered by the user, we want nicely formatted output (what is the default). But when running in GitHub CI, I'd like to have github reporter so that it can be parsed by GitHub.

With ruff, we achieve the same by setting RUFF_OUTPUT_FORMAT=github in the CI environment, and having something similar for biome would be great.

[ematipico]

That's a nice addition!