add pod version to Readme
add pod version to Readme

jj101k/QRCode,boxenjim/QRCode,keyclipse/QRCode,rromanchuk/QRCode,dave256/QRCode,jj101k/QRCode,nanoxd/QRCode,dave256/QRCode,eeschimosu/QRCode,boxenjim/QRCode,andrewkkchan/QRCode,rromanchuk/QRCode,rromanchuk/QRCode,keyclipse/QRCode,aschuch/QRCode,tasselx/QRCode-Swift,aschuch/QRCode,dave256/QRCode,tasselx/QRCode-Swift,andrewkkchan/QRCode,andrewkkchan/QRCode,nanoxd/QRCode,eeschimosu/QRCode,eeschimosu/QRCode