Update dead link in extending.rst

[danielmichaels]

brief description what this PR will do, e.g. fixes broken dissection of XXX

Improve Documentation

Reading over the docs, the link to Wifitap is dead. I found Wifitap's GitHub repo and replaced the link with it.

[codecov]

Codecov Report

Merging #2064 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2064      +/-   ##
==========================================
- Coverage   86.34%   86.33%   -0.01%     
==========================================
  Files         197      197              
  Lines       44603    44603              
==========================================
- Hits        38514    38510       -4     
- Misses       6089     6093       +4

Impacted Files	Coverage Δ
scapy/automaton.py	81.81% <0%> (-0.56%)	⬇️
scapy/layers/inet6.py	87.99% <0%> (-0.3%)	⬇️
scapy/sendrecv.py	85.37% <0%> (+0.16%)	⬆️
scapy/asn1/ber.py	83.09% <0%> (+0.28%)	⬆️
scapy/layers/tls/record.py	92.1% <0%> (+0.87%)	⬆️

[gpotter2]

The repo you've provided looks pretty dead :/
It seems that GDSSecurity/wifitap#1 actually makes it work with recent Scapy versions, but I doubt it really does with master :/

I'll ask there if the project is dead. If it is, it might be a better idea to remove the link

[p-l-]

We are keeping that link for historical & sentimental reasons. I think we should just add a note to state that Wifitap is no longer updated... but I'd like to keep the current link.

[danielmichaels]

We are keeping that link for historical & sentimental reasons. I think we should just add a note to state that Wifitap is no longer updated... but I'd like to keep the current link.

@p-l-, does a change like this suit?