python-flufl.bounce-4.0-bp156.1.1

- tag sle15 build for new python stack

- Remove not needed dependency python-six

- Skip building for python2

- Enable multiflavor so that we can pin mailmain to Python 3.9

- Update to version 4.0
  - Added another string to the stop looking strings in the yahoo
    detector.
  - Detectors are now run in a defined order and stop on the
    first detection.
  - Fixed microsoft.py which has been broken forever.
  - Added recognition for yet another non-complaint Yahoo DSN.
  - Added recognition for a non-compliant DSN from an unknown
    MTA.
  - Added recognition for a non-compliant opensmtpd DSN with
    Action: error.
  - Fixed simplmatch.py to not return results that don't resemble
    email addresses. (LP: #1859011)

- update LICENSE to current state
- modified sources
  % LICENSE

- call spec-cleaner

- initial version 3.0, required by python-mailman [SLE-7686]