bump version to 0.3.0b2
bump version to 0.3.0b2

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