feat: add max messages batching for Cloud Storage subscriptions (#1956)

- [ ] Regenerate this pull request now.

PiperOrigin-RevId: 651799920

Source-Link: https://togithub.com/googleapis/googleapis/commit/8148b2fde13d3ed79cf285e9c529572aa8cf6ef7

Source-Link: https://togithub.com/googleapis/googleapis-gen/commit/1a41634b2c8b7c5c7ea79e9d86f514b532f17d08
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiMWE0MTYzNGIyYzhiN2M1YzdlYTc5ZTlkODZmNTE0YjUzMmYxN2QwOCJ9

.eslintignore

@@ -1,9 +1,7 @@
 **/node_modules
-**/coverage
-test/fixtures
+**/.coverage
 build/
 docs/
-owl-bot-staging/
 protos/
+system-test/
 samples/generated/
-system-test/**/fixtures

protos/google/pubsub/v1/pubsub.proto

@@ -1240,6 +1240,10 @@ message CloudStorageConfig {
   // be exceeded in cases where messages are larger than the limit.
   int64 max_bytes = 7 [(google.api.field_behavior) = OPTIONAL];
 
+  // Optional. The maximum number of messages that can be written to a Cloud
+  // Storage file before a new file is created. Min 1000 messages.
+  int64 max_messages = 8 [(google.api.field_behavior) = OPTIONAL];
+
   // Output only. An output-only field that indicates whether or not the
   // subscription can receive messages.
   State state = 9 [(google.api.field_behavior) = OUTPUT_ONLY];