Release 0.9.8

What's Changed

• Base64 decode by @qicosmos in #722
• fix base64 decode by @qicosmos in #723
• Fix smtp client by @qicosmos in #724
• Improve smtp client by @qicosmos in #725
• add header by @qicosmos in #726

Full Changelog: 0.9.7...0.9.8