Update changelogs from fern repo (#5294)

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

Author: fern-support

fern/products/cli-api-reference/cli-changelog/2026-05-01.mdx

@@ -0,0 +1,11 @@
+## 5.6.0
+**`(feat):`** Add `fern automations upgrade` command that wraps `fern upgrade` and
+`fern generator upgrade` into a single invocation with structured JSON
+output (`--json`). Designed for consumption by the fern-upgrade GitHub
+Action.
+
+
+**`(fix):`** Replace brittle hardcoded changelog URL map in `upgradeGenerator.ts` with
+a regex-based derivation that supports all current and future generators.
+
+