chore: Name the default export 'pluginXML'

[regseb]

When importing the default export, it's recommended to use the same name as the exported variable (cf. import-x/no-rename-default).

The variable name exported by plugin-xml is plugin. With the following configuration:

import pluginXML from "@prettier/plugin-xml";

const config = {
  plugins: [pluginXML],
  xmlQuoteAttributes: "double",
};

export default config;

ESLint reports this error:

Caution: plugin.js has a default export plugin. This imports plugin as pluginXML. Check if you meant to write import plugin from '@prettier/plugin-xml' instead

---

With this pull request, we will be able to use the name pluginXML