Allow setting a custom HTTP method in CacheBuster (#26528)

Co-authored-by: Jorijn Schrijvershof <jorijn@jorijn.com>

lib/http_extensions.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+# Monkey patching until https://github.com/httprb/http/pull/757 is merged
+unless HTTP::Request::METHODS.include?(:purge)
+  module HTTP
+    class Request
+      METHODS = METHODS.dup.push(:purge).freeze
+    end
+  end
+end