Remove Ruby 3.5 from branches.yml

On the "Ruby Maintenance Branches" page, both Ruby 3.5 and Ruby 4.0 are
listed as branches:
https://www.ruby-lang.org/en/downloads/branches/

Ruby 3.5 was renamed to Ruby 4.0, so there is no separate maintenance
policy for Ruby 3.5. Similar to the relationship between Ruby 2.8 and
Ruby 3.0, Ruby 3.5 should be removed and only Ruby 4.0 should remain.

Author: koic

_data/branches.yml

@@ -13,11 +13,6 @@
   date:
   eol_date:
 
-- name: 3.5
-  status: preview
-  date:
-  eol_date:
-
 - name: 3.4
   status: normal maintenance
   date: 2024-12-25