Update changelogs from fern repo (#4930)

Co-authored-by: dsinghvi <10870189+dsinghvi@users.noreply.github.com>

Author: fern-support

fern/products/cli-api-reference/cli-changelog/2026-04-14.mdx

@@ -1,3 +1,7 @@
+## 4.68.4
+**`(fix):`** Deduplicate global headers when merging IRs from multiple OpenAPI specs. Previously, if multiple specs shared the same `globalHeaderOverrides` from `generators.yml`, the same header would appear once per spec in the merged IR.
+
+
 ## 4.68.3
 **`(fix):`** Fix global headers from `generators.yml` not appearing in documentation endpoints. The new OpenAPI v3 parser (`openapi-to-ir`) had a TODO placeholder but never converted `globalHeaderOverrides` into IR headers.