Update cfp deadline PyCon NL

The deadline has been extended.

Author: raviselker

_data/conferences.yml

@@ -159,7 +159,7 @@
   year: 2025
   link: https://pycon-nl.org/
   cfp_link: https://docs.google.com/forms/d/e/1FAIpQLSdv-shKzLId7WMwxmVNfSsWZjCd4eNuB7ExKvu_B3s4yONR-Q/viewform
-  cfp: '2025-08-01 23:59:00'
+  cfp: '2025-08-17 23:59:00'
   place: Utrecht, Netherlands
   start: 2025-10-16
   end: 2025-10-16