docs: fold v2.2.1 notes into v2.3.0

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## v2.3.0
 
-This release expands on the Security Insights v2.1.0 specification by adding a new micro-CLI for non-library use cases. It also contains discovery and fetching improvements to the library.
+This release expands on the Security Insights v2.2.0 specification by adding a new micro-CLI for non-library use cases. It also contains discovery and fetching improvements to the library.
 
 ### Features
 
@@ -11,11 +11,6 @@ This release expands on the Security Insights v2.1.0 specification by adding a n
 - `si fetch` command (`v2/cmd/si`) runs discovery and parsing over many targets and prints machine-readable JSON, for catalogues and dashboards built on Security Insights data. Each result carries a status of `ok`, `not-found`, `invalid` or `error`; the command exits 2 when any target hit a transport `error`, so an incomplete batch is never mistaken for a clean one
 - `si.Load` returns `si.ErrParentUnavailable` when the parent named in `project-si-source` cannot be fetched for a reason unrelated to its content; `si fetch` reports that as `error`, not `invalid`
 - All GitHub API calls, including the existing `si.Read`, now authenticate with `GITHUB_TOKEN` when set and honour `GITHUB_API_URL`; all requests time out after 30 seconds
-
-## v2.2.1
-
-### Features
-
 - `SecurityInsightsFilenames()` returns both accepted names, `security-insights.yml` and `security-insights.yaml`, matching the spec
 
 ### Deprecations