Update changelogs from fern repo (#991)

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

Author: fern-support

fern/products/sdks/overview/go/changelog/2025-09-25.mdx

@@ -1,3 +1,7 @@
+## 1.13.1
+**`(fix):`** Stop generating go.mod file in go-v2 sdk generation.
+
+
 ## 1.13.0
 **`(feat):`** Add support for PR mode for self-hosted/local sdk generation