FIX: Exclude `DELETE` methods from invalid request with payload.

Follow-up 105d560177

Our client side code is sending params as part of the request payload so
that is going to be tricky to fix.

lib/middleware/anonymous_cache.rb

@@ -307,7 +307,7 @@ module Middleware
       @app = app
     end
 
-    PAYLOAD_INVALID_REQUEST_METHODS = ["GET", "DELETE", "HEAD"]
+    PAYLOAD_INVALID_REQUEST_METHODS = ["GET", "HEAD"]
 
     def call(env)
       if PAYLOAD_INVALID_REQUEST_METHODS.include?(env[Rack::REQUEST_METHOD]) &&