Update code of conduct

[tsnoam]

Following the recent events in the users group.

[codecov]

Codecov Report

Merging #980 into master will decrease coverage by 0.96%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #980      +/-   ##
==========================================
- Coverage   91.67%   90.71%   -0.97%     
==========================================
  Files         103      103              
  Lines        4050     4050              
  Branches      639      610      -29     
==========================================
- Hits         3713     3674      -39     
- Misses        198      220      +22     
- Partials      139      156      +17

Impacted Files	Coverage Δ
telegram/files/inputfile.py	79.72% <0%> (-10.82%)	⬇️
telegram/utils/helpers.py	73.52% <0%> (-8.83%)	⬇️
telegram/ext/messagequeue.py	62.65% <0%> (-7.23%)	⬇️
telegram/games/game.py	94.28% <0%> (-5.72%)	⬇️
telegram/message.py	91.72% <0%> (-5.27%)	⬇️
telegram/base.py	94.87% <0%> (-5.13%)	⬇️
telegram/utils/webhookhandler.py	95.18% <0%> (-2.41%)	⬇️
telegram/utils/request.py	66.07% <0%> (-0.9%)	⬇️
telegram/bot.py	87.39% <0%> (-0.13%)	⬇️