add 1.6.1 announcement [ci skip]
add 1.6.1 announcement [ci skip]

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