bump version 0.3.1
bump version 0.3.1

aebrahim/cobrapy,JuBra/cobrapy,JuBra/cobrapy,aebrahim/cobrapy,jeicher/cobrapy,zakandrewking/cobrapy,zakandrewking/cobrapy,jerkos/cobrapy,jerkos/cobrapy,jeicher/cobrapy