Pim-dm

Remove tcpdump dependency.

Better exception handling of config input files.

Thank you leoplo for the PR! :1st_place_medal:

Setup.py no longer reads requirements.txt file. Instead dependencies are defined explicitly.

Fix bug on IPv6 PIM-DM implementation. Drop capability was crashing the full PIM-DM IPv6 transmission of control messages.

Bump required MLD version... This MLD version includes bugfixes.

Thanks to leoplo for his contribution on this release!

Update version includes a fix on the README file (typo)

Thank you leoplo for the fix

Include Python 3.9 as supported