Rename ABL branch (#2358)

Co-authored-by: Dante Soares <[email protected]>

Author: philschatz

config/secrets.yml

@@ -61,7 +61,7 @@ development:
       url: <%= ENV['OPENSTAX_ACCOUNTS_URL'] || 'http://localhost:2999' %>
       stub: <%= ActiveModel::Type::Boolean.new.cast(ENV.fetch('OPENSTAX_ACCOUNTS_STUB', true)) %>
     content:
-      abl_url: <%= ENV['OPENSTAX_CONTENT_ABL_URL'] || 'https://raw.githubusercontent.com/openstax/content-manager-approved-books/master/approved-book-list.json' %>
+      abl_url: <%= ENV['OPENSTAX_CONTENT_ABL_URL'] || 'https://raw.githubusercontent.com/openstax/content-manager-approved-books/main/approved-book-list.json' %>
       archive_path: <%= ENV['OPENSTAX_CONTENT_ARCHIVE_PATH'] || 'apps/archive' %>
       bucket_name: <%= ENV['OPENSTAX_CONTENT_BUCKET_NAME'] %>
       domain: <%= ENV['OPENSTAX_CONTENT_DOMAIN'] || 'openstax.org' %>