Not urgent, so feel free to merge and release when you have time.

Starting with biome 2.0, they now allow specifying a configuration file directly. Previously, we had to specify a folder that had to contain a biome.json file. This can be useful when you need to adjust some biome settings for use with spotless. biome now allows creating a config file that inherits from another file, and overwrite only selected settings.

This PR adjust the spotless wrapper for biome to allow specifying configuration files directly, and adds a test for that scenario.

For example:

// biome-spotless.json
{
  "extends": ["./biome.json"],
  "files": {
    "includes": ["**"]
  }
}

// biome.json
{
  "$schema": "https://biomejs.dev/schemas/2.1.1/schema.json",
  "formatter": {
    "enabled": true,
    "indentStyle": "space",
    "indentWidth": 2,
    "lineWidth": 120
  },
  "files": {
    "maxSize": 5097152,
    "includes": []
  }
}

<biome>
  <configPath>${project.basedir}/biome-spotless.json</configPath>
</biome>

After creating the PR, please add a commit that adds a bullet-point under the [Unreleased] section of CHANGES.md, plugin-gradle/CHANGES.md, and plugin-maven/CHANGES.md which includes:

• a summary of the change
• either
  • a link to the issue you are resolving (for small changes)
  • a link to the PR you just created (for big changes likely to have discussion)

If your change only affects a build plugin, and not the lib, then you only need to update the plugin-foo/CHANGES.md for that plugin.

If your change affects lib in an end-user-visible way (fixing a bug, updating a version) then you need to update CHANGES.md for both the lib and all build plugins. Users of a build plugin shouldn't have to refer to lib to see changes that affect them.

This makes it easier for the maintainers to quickly release your changes :)