Update changelogs from fern repo (#2500)

Author: fern-support

fern/products/sdks/overview/csharp/changelog/2025-12-03.mdx

@@ -1,3 +1,34 @@
+## 2.10.0
+**`(feat):`** Add support for flexible `output-path` configuration that allows specifying different paths 
+for the library project, test project, solution file, and other files (README.md, reference.md).
+
+Configuration options:
+* Simple string: `output-path: src` - all projects go to that path
+* Object with specific paths:
+  - `library`: path for the library project (default: "src")
+  - `test`: path for the test project (default: "src")
+  - `solution`: path for the solution file (default: ".")
+  - `other`: path for README.md, reference.md, and other files (default: ".")
+
+Example generators.yml configuration:
+```yml
+groups:
+  dotnet-sdk:
+    generators:
+      - name: fernapi/fern-csharp-sdk
+        version: 2.10.0
+        config:
+          output-path:
+            library: src/MyApi
+            test: test/MyApi.Test
+            solution: .
+            other: src/MyApi
+```
+
+The generated CI workflow and project references are automatically updated to use the configured paths.
+Note: `.github`, `.fern`, `.editorconfig`, `.gitignore`, and `.fernignore` are always generated in the root output folder.
+
+
 ## 2.9.9
 **`(fix):`** Retries now check `Retry-After` and `X-RateLimit-Reset` headers before defaulting to 
 exponential backoff with jitter.