added pyserial to requirements
added pyserial to requirements

dyegocantu/pingo-py,tylerdave/pingo-py,Vido/pingo,dyegocantu/pingo-py,tylerdave/pingo-py,pingo-io/pingo-py,pingo-io/pingo-py,Ladeia/pingo-py,Ladeia/pingo-py,lamenezes/pingo-py,Vido/pingo,lamenezes/pingo-py