Change CFP status to 'Cancelled' for PyCon EE

Updated the CFP status for PyCon EE to 'Cancelled' and added a new field for the original CFP deadline.

Author: JesperDramsch

_data/conferences.yml

@@ -645,7 +645,8 @@
   year: 2026
   link: https://pycon.ee/
   cfp_link: https://docs.google.com/forms/d/e/1FAIpQLSewbFKG6BEsGXR9ilgsW1wqfmzRR0Pf9XDO5WXTFhrcgrrN3g/viewform
-  cfp: '2026-02-28 23:59:00'
+  cfp: Cancelled
+  cfp_ext: '2026-02-28 23:59:00'
   place: Tallinn, Estonia
   start: 2026-10-08
   end: 2026-10-09