[BUGFIX] emit silent error if css linting fails

gulp/css.js

@@ -100,7 +100,10 @@ gulp.task('css:qa', function() {
 	return gulp.src([settings.getPath() + '/' + config.directories.sass + '/**/*.scss', '!**/*scsslint_tmp*.scss'].concat(config.css.excludeFromQa))
 		.pipe(plugins.scssLint({
 			customReport: plugins.scssLintStylish
-		}));
+		}))
+		.on('error', function(error) {
+			plugins.util.log(error);
+		});
 });
 
 gulp.task('css', gulp.series(gulp.parallel('css:sprites', 'css:svg', 'css:qa'), processCss, 'css:abovethefold'));