Fix CSW note in the README
Fix CSW note in the README

Addresses review comment from  tomkralidis.

datagovuk/OWSLib,b-cube/OWSLib,QuLogic/OWSLib,kwilcox/OWSLib,daf/OWSLib,tomkralidis/OWSLib,geopython/OWSLib,gfusca/OWSLib,bird-house/OWSLib,daf/OWSLib,datagovuk/OWSLib,geographika/OWSLib,mbertrand/OWSLib,jachym/OWSLib,datagovuk/OWSLib,jaygoldfinch/OWSLib,KeyproOy/OWSLib,Jenselme/OWSLib,ocefpaf/OWSLib,robmcmullen/OWSLib,jaygoldfinch/OWSLib,JuergenWeichand/OWSLib,menegon/OWSLib,daf/OWSLib,kalxas/OWSLib,dblodgett-usgs/OWSLib