Update changelogs from fern repo (#4258)

Co-authored-by: patrickthornton <70873350+patrickthornton@users.noreply.github.com>

Author: fern-support

fern/products/sdks/overview/csharp/changelog/2026-03-13.mdx

@@ -1,3 +1,7 @@
+## 2.27.1
+**`(fix):`** Fix retry test assertions to match the SDK's indented JSON serialization.
+
+
 ## 2.27.0
 **`(feat):`** Improve gRPC code generation with the following:
  1. Updated enum representation and .ToProto + .FromProto mappers.