Add compatibility with Patron 0.4.20
Add compatibility with Patron 0.4.20

Version 0.4.20 of the Patron gem uses strings instead of symbols for
validating valid request actions.

mauricionr/faraday,ekampp/faraday,pvdb/faraday,iamjarvo/faraday,prcongithub/faraday,AvaelKross/faraday,lostisland/faraday,grosser/faraday,hrysd/faraday,engineyard/faraday,ekampp/faraday,hrysd/faraday,hstrowd/faraday,daviswahl/faraday,jhass/faraday,zhaoxl/faraday,jhass/faraday,mauricionr/faraday,santiagodoldan/faraday,davoclavo/faraday,engineyard/faraday,mehulkar/faraday,spyofchina/faraday,luvtechno/faraday,hstrowd/faraday,davidcornu/faraday,mehulkar/faraday,zanker/faraday,stayhero/faraday,nevans/faraday,luvtechno/faraday,zhaoxl/faraday,ngpestelos/faraday,ngpestelos/faraday,flower-pot/faraday,stayhero/faraday,nevans/faraday,santiagodoldan/faraday,iamjarvo/faraday,grosser/faraday,lostisland/faraday,pvdb/faraday,daviswahl/faraday,davoclavo/faraday,flower-pot/faraday,AvaelKross/faraday,davidcornu/faraday,zanker/faraday,coinbase/faraday,coinbase/faraday,spyofchina/faraday,prcongithub/faraday