Update info file to reflect lack of D9 compatibility.

better_exposed_filters.info.yml

 name: Better Exposed Filters
 description: Provides advanced options (e.g. links, checkboxes, or other widgets) to exposed Views elements.
 core: 8.x
-core_version_requirement: ^8 || ^9
+core_version_requirement: ^8
 type: module
 package: Views
 dependencies: