chore: update env.example to match latest main

Author: Joyakis

env.example

@@ -29,10 +29,3 @@
 # https://docs.github.com/en/rest/authentication/authenticating-to-the-rest-api
 
 # GH_TOKEN =
-# "The flickr developer guide: https://www.flickr.com/services/developer/"
-
-# FLICKR_API_KEY =
-# FLICKR_API_SECRET =
-
-# "Europeana Search API Documentation: https://europeana.atlassian.net/wiki/spaces/EF/pages/2385739812/Search+API+Documentation#Request
-# EUROPEANA_API_KEY =