add rtd link [ci skip]
add rtd link [ci skip]

ricardogsilva/pycsw,kalxas/pycsw,ckan-fcd/pycsw-fcd,mwengren/pycsw,geopython/pycsw,tomkralidis/pycsw,ckan-fcd/pycsw-fcd,benhowell/pycsw,PublicaMundi/pycsw,tomkralidis/pycsw,geopython/pycsw,bukun/pycsw,ocefpaf/pycsw,ricardogsilva/pycsw,ingenieroariel/pycsw,mwengren/pycsw,tomkralidis/pycsw,kevinpdavies/pycsw,ricardogsilva/pycsw,PublicaMundi/pycsw,kalxas/pycsw,rouault/pycsw,ingenieroariel/pycsw,rouault/pycsw,bukun/pycsw,bukun/pycsw,ocefpaf/pycsw,kalxas/pycsw,geopython/pycsw,kevinpdavies/pycsw,benhowell/pycsw