feat: support target file and directories

[wellwelwel]

Now it's possible to use both target dir and files to Poku:

npx poku test/my-file.js
npx poku test/my-file.ts

npx poku --parallel test/my-file-a.js,my-file-b.ts

npx poku --parallel test/my-file-a.js,test/my-dir,my-file-b.ts