fix(makeProgram): specify .mjs and .cjs config files are allowed

[wojtekmaj]

Looking at the source code:

svgo/lib/svgo-node.js

Lines 39 to 50 in 2442f74

	const js = path.join(dir, 'svgo.config.js');
	if (await isFile(js)) {
	return await importConfig(js);
	}
	const mjs = path.join(dir, 'svgo.config.mjs');
	if (await isFile(mjs)) {
	return await importConfig(mjs);
	}
	const cjs = path.join(dir, 'svgo.config.cjs');
	if (await isFile(cjs)) {
	return await importConfig(cjs);
	}

it looks to me like not only .js, but also .mjs, and .cjs extensions are allowed in config files. This PR aligns the help text with the actual behavior.

[SethFalco]

Good catch! Had a nitpick, but if we can just update the wording, I'd be happy to merge this.

[SethFalco]

LGTM! Thanks again! 👍🏽