Update Code of Conduct to Contributor Covenant version 1.4
Update Code of Conduct to Contributor Covenant version 1.4

The main difference is that it lists some examples of positive things.

kaushik94/sympy,jerli/sympy,drufat/sympy,Arafatk/sympy,hargup/sympy,Titan-C/sympy,rahuldan/sympy,kaichogami/sympy,Titan-C/sympy,sampadsaha5/sympy,sampadsaha5/sympy,souravsingh/sympy,postvakje/sympy,jaimahajan1997/sympy,souravsingh/sympy,aktech/sympy,madan96/sympy,yashsharan/sympy,chaffra/sympy,kaushik94/sympy,yashsharan/sympy,chaffra/sympy,hargup/sympy,Arafatk/sympy,Curious72/sympy,kaichogami/sympy,madan96/sympy,skidzo/sympy,ChristinaZografou/sympy,ChristinaZografou/sympy,ChristinaZografou/sympy,jaimahajan1997/sympy,sampadsaha5/sympy,drufat/sympy,aktech/sympy,kaushik94/sympy,yashsharan/sympy,Titan-C/sympy,madan96/sympy,chaffra/sympy,lindsayad/sympy,hargup/sympy,mafiya69/sympy,lindsayad/sympy,rahuldan/sympy,postvakje/sympy,jerli/sympy,kaichogami/sympy,rahuldan/sympy,Curious72/sympy,drufat/sympy,jaimahajan1997/sympy,Arafatk/sympy,skidzo/sympy,skidzo/sympy,aktech/sympy,mafiya69/sympy,jerli/sympy,mafiya69/sympy,Curious72/sympy,lindsayad/sympy,postvakje/sympy,souravsingh/sympy