update POT

git-svn-id: https://plugins.svn.wordpress.org/updraftplus/trunk@877811 b8457f37-d9ea-0310-8a92-e5e31aec5664
update Dutch translation

git-svn-id: https://plugins.svn.wordpress.org/updraftplus/trunk@877812 b8457f37-d9ea-0310-8a92-e5e31aec5664