Add asyncRetrySimple & asyncRetryCustom

What's Changed

• Update asyncRetrySimple description by @Marketionist in #39
• Update asyncRetrySimple by @Marketionist in #40
• Add jsdoc for dateTime by @Marketionist in #41
• Add asyncRetryCustom by @Marketionist in #42
• Add description for asyncRetryCustom by @Marketionist in #43

Full Changelog: v1.6.0...v1.7.0