update changelogs

Author: kafkas

fern/products/sdks/overview/swift/changelog/2025-09-05.mdx

@@ -1,3 +1,7 @@
+## 0.12.2
+**`(fix):`** Request headers in endpoint methods are now restricted to String types only.
+
+
 ## 0.12.1
 **`(fix):`** Required bearer token param in root client convenience initializer is now correctly marked as `@escaping` and the relevant argument is now initialized properly.