Update changelogs from fern repo (#506)

Co-authored-by: dsinghvi <[email protected]>

Author: fern-support

fern/products/sdks/overview/ruby/changelog/2025-08-18.mdx

@@ -1,3 +1,6 @@
+## 1.0.0-rc8
+**`(fix):`** The client argument on the nested resource is now a keyword argument.
+
 ## 1.0.0-rc7
 **`(fix):`** Update the Union type to not remove the discriminant from the value.