Log Message:
mitmproxy: Update to 8.1.0

pkgsrc changes:
 - Now needs Python>=3.9 per upstream
 - Further relax py-cryptography needs (seems to runs fine also with older
   py-cryptography) because in pkgsrc we do not have yet cryptography>=36.

Changes:
## 15 May 2022: mitmproxy 8.1.0

* Mostly a Bug fix release
* DNS support
* Mitmproxy now requires Python 3.9 or above.

## 19 March 2022: mitmproxy 8.0.0
### Major Changes

* Major improvements to the web interface
* Event hooks can now be async
* New `tls_{established,failed}_{client,server}` event hooks to record
  negotiation success/failure

### Security Fixes

* CVE-2022-24766: Fix request smuggling vulnerability reported by @zeyu2001