mailu/towncrier/newsfragments
bors[bot] 1f2ae521d7 Merge
1084: Allow subnet with host bit set in setup r=mergify[bot] a=hoellen

## What type of PR?
bug-fix

## What does this PR do?
This allows to set the host bit in the subnet while using the [setup](https://setup.mailu.io/1.6/). The host bits are now masked out to determine the appropriate network address. This means that e.g. `172.17.0.1/12` is now considered as `172.17.0.0/12`.
So new users are not confused by error messages while setup a new Mailu instance (as you can see the multiple requests in the Matrix chat).

ref: https://docs.python.org/3/library/ipaddress.html#ipaddress.IPv4Network

### Related issue(s)
closes  

## Prerequistes
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [x] In case of feature or enhancement: documentation updated accordingly
- [x] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/guide.html#changelog) entry file.


Co-authored-by: hoellen <dev@hoellen.eu>
..
820.bugfix Use ldez/traefik-certs-dumper in certificate dumper, and make more robust
867.bugfix Make aliases case-insensitive (too)
891.feature Update fetchmail to selfbuilt 7.0.0-alpha
916.doc fix destination of changelog file ()
958.feature Add authentication for email relays
988.feature add sidebar toggle button
1009.misc move changelog to the right directory
1049.feature Add towncrier newsfragments
1051.feature Add towncrier newsfragments
1066.feature Update password in commandline
1070.feature update changelog
1071.feature update changelog
1075.bugfix Create 1075.bugfix
1082.feature Update changelog
1083.bugfix Allow subnet with host bit set in setup