remove unused export

packages/hydrooj/src/model/problem.ts

@@ -5,7 +5,7 @@ import path from 'path';
 import AdmZip from 'adm-zip';
 import fs from 'fs-extra';
 import yaml from 'js-yaml';
-import { escapeRegExp, pick } from 'lodash';
+import { pick } from 'lodash';
 import { Filter, ObjectId } from 'mongodb';
 import type { Readable } from 'stream';
 import { Logger, size, streamToBuffer } from '@hydrooj/utils/lib/utils';