fixup! STF-322: Document transport-failure retry in README and CHANGELOG

Author: oschwald

CHANGELOG.md

@@ -6,6 +6,10 @@ CHANGELOG
 
 * Added `WebServiceClient.Builder.maxRetries(int)` to bound transport-failure
   retries (default 1; set 0 to disable). See the README for retry semantics.
+  **Behavior change:** previously, transient transport failures (connection
+  reset, broken pipe, etc.) surfaced to callers immediately. They are now
+  retried once by default; pass `.maxRetries(0)` to restore the prior
+  behavior.
 
 5.0.2 (2025-12-08)
 ------------------