update changelogs

Author: dsinghvi

fern/products/sdks/generators/python/changelog/2026-04-30.mdx

@@ -1,3 +1,10 @@
+## 5.9.0
+**`(feat):`** Add `retryStatusCodes` config with `"legacy"` and `"recommended"` modes. Legacy (default)
+preserves current behavior (408, 409, 429, >= 500). Recommended retries only transient
+codes (408, 409, 429, 502, 503, 504), avoiding idempotency issues with 500. A 6.0.0
+migration auto-pins legacy for upgrading users.
+
+
 ## 5.8.4
 **`(chore):`** Bump @fern-api/generator-cli to 0.9.21, which includes @fern-api/replay
 0.14.0 with fixes for silent customization loss across apply and resolve