test: add explicit imports for jest functions (#128)

* test: add explicit imports for `jest` functions

* add workaround for non-`.spec.ts` file

test/asar-utils.spec.ts

@@ -1,6 +1,7 @@
 import * as path from 'path';
 
 import { AsarMode, detectAsarMode, generateAsarIntegrity } from '../src/asar-utils';
+import { describe, expect, it } from '@jest/globals';
 
 const asarsPath = path.resolve(__dirname, 'fixtures', 'asars');
 const appsPath = path.resolve(__dirname, 'fixtures', 'apps');