chore: update docs with fed v2.12 changelog entry (#3350)

Signed-off-by: Benjamin <5719034+bnjjj@users.noreply.github.com>
Co-authored-by: Michelle Mabuyo <michelle@apollographql.com>
Co-authored-by: Benjamin <5719034+bnjjj@users.noreply.github.com>

Author: 3 people

docs/source/schema-design/federated-schemas/reference/versions.mdx

@@ -26,6 +26,27 @@ For a comprehensive changelog for Apollo Federation and its associated libraries
 
 - If you maintain a [subgraph-compatible library](/graphos/reference/federation/compatible-subgraphs), consult this article to stay current with recently added directives. All of these directive definitions are also listed in the [subgraph specification](/graphos/reference/federation/subgraph-spec/#subgraph-schema-additions).
 
+## v2.12
+
+<hr/>
+
+| First release | Available in GraphOS? | Minimum router version |
+| ------------- | --------------------- | ---------------------- |
+| **November 2025** | **Yes** | **`2.8.0`** |
+
+Federation v2.12 is a prerequisite for the Connector specification version 0.3.
+[Learn more.](/graphos/schema-design/connectors/directives)
+
+#### Directive changes
+
+#### `@cacheTag`
+
+Introduced. This directive allows you to set cache tags that can be associated with cached entries using [response caching](/graphos/routing/performance/caching/response-caching/overview). Learn more about how to invalidate specific data in your schema [using `@cacheTag`](/graphos/routing/performance/caching/response-caching/invalidation#by-cache-tag).
+
+```graphql showLineNumbers=false disableCopy=true
+directive @cacheTag(format: String!) repeatable on FIELD_DEFINITION | OBJECT
+```
+
 ## v2.11
 
 <hr/>