test: removed os from tests/bin/polykey.test.ts as is no longer used

Author: CMCDragonkai

tests/bin/polykey.test.ts

@@ -1,6 +1,5 @@
 import fs from 'fs';
 import path from 'path';
-import os from 'os';
 import readline from 'readline';
 import Logger, { LogLevel, StreamHandler } from '@matrixai/logger';
 import * as testUtils from '../utils';