Update changelogs from fern repo (#2939)

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

Author: fern-support

fern/products/cli-api-reference/cli-changelog/2025-12-23.mdx

@@ -1,3 +1,7 @@
+## 3.31.0
+**`(fix):`** Add a `--dynamic-ir-only` flag to SDK generation to enable access to dynamic snippets from SDKs without regenerating the entire SDK.
+
+
 ## 3.30.6
 **`(fix):`** Only upload dynamic IR for SDK generation after confirmed success and when not in preview mode.