iRedMail-1.6.0 has been released, and introduce Spider Email Archiver (beta)

[Zhang Huangbin]

Dear all,

iRedMail-1.6.0 has been released, it's a small bug fix release, visit
our forum for detailed release notes:
https://forum.iredmail.org/topic19008.html

## Introduce "Spider Email Archiver"

Spider Email Archiver is a lightweight, resource efficient email archiving
software developed by iRedMail team, you can find more details on
its own web site:
https://spider-archiver.com/

It's still in beta stage and not production ready, we'd like to hear from you.
Feedbacks, suggestions are always welcome. :)

----
Zhang Huangbin, founder of:
- iRedMail: Open source email server solution: https://www.iredmail.org/
- Spider: On-Premises Email Archiving Software: https://spider-archiver.com/