fix(gcp_pubsub source): Remove Tonic default 4MB decode size limit (#…

…22091)

* Remove Tonic default 4MB decode size limit

* Changelog entry

* Update changelog.d/22090_remove_gcp_pubsub_msg_size_limit.fix.md

---------

Co-authored-by: Jesse Szwedko <jesse@szwedko.me>
Co-authored-by: Jesse Szwedko <jesse.szwedko@datadoghq.com>

changelog.d/22090_remove_gcp_pubsub_msg_size_limit.fix.md

@@ -0,0 +1,3 @@
+The `gcp_pubsub` source no longer has a 4MB message size limit.
+
+authors: sbalmos

src/sources/gcp_pubsub.rs

@@ -479,7 +479,9 @@ impl PubsubSource {
                 }
                 Ok(req)
             },
-        );
+        )
+        // Tonic added a default of 4MB in 0.9. This replaces the old behavior.
+        .max_decoding_message_size(usize::MAX);
 
         let (ack_ids_sender, ack_ids_receiver) = mpsc::channel(ACK_QUEUE_SIZE);