v3.0.0

• [feat] add a new experimental EPT mode, which can get less rate limit than the legacy mode. Just try it! (See the README for the limitations)
• [feat] still use 1000 as the default maxTextLen. 5000 is only available in China.
• [refactor] cookie is no longer passed in HTTP requests.
• [fix] fix potential JSON parsing error brought by trailing comma.
• [chore] update default user-agent.