👷 allow hygiene to run on a single file

build/gulpfile.hygiene.js

@@ -238,6 +238,14 @@ if (require.main === module) {
 	cp.exec('git config core.autocrlf', (err, out) => {
 		const skipEOL = out.trim() === 'true';
 
+		if (process.argv.length > 2) {
+			return hygiene(process.argv.slice(2), { skipEOL: skipEOL }).on('error', err => {
+				console.error();
+				console.error(err);
+				process.exit(1);
+			});
+		}
+
 		cp.exec('git diff --cached --name-only', { maxBuffer: 2000 * 1024 }, (err, out) => {
 			if (err) {
 				console.error();