Add release notes for 8.1.1 (#7704)

Author: stevejgordon

docs/release-notes/release-notes-8.1.1.asciidoc

@@ -0,0 +1,72 @@
+[[release-notes-8.1.1]]
+== Release notes v8.1.1
+
+[discrete]
+=== Bug fixes
+
+- https://github.com/elastic/elasticsearch-net/pull/7667[#7667] Fix SQL missing 
+Rows on QueryResponse (issue: https://github.com/elastic/elasticsearch-net/issues/7663[#7663])
+- https://github.com/elastic/elasticsearch-net/pull/7676[#7676] Ensure async client 
+methods pass through cancellation token (issue: https://github.com/elastic/elasticsearch-net/issues/7665[#7665])
+
+[discrete]
+=== Enhancements
+
+- https://github.com/elastic/elasticsearch-net/pull/7684[#7684] Regenerated code 
+with latest spec fixes for 8.7
+
+[discrete]
+=== Breaking changes
+
+This release includes the following breaking changes as a result of specification fixes:
+
+[discrete]
+==== AsyncSearch and MultisearchBody KnnQuery
+
+The type for the `SubmitAsyncSearchRequest.Knn` and `MultisearchBody.Knn` properties 
+has changed to an `ICollection<KnnQuery>` from a single `KnnQuery` since it is 
+possible to include more than one query in a request.
+
+*_Before_*
+
+[source,csharp]
+----
+public sealed partial class SubmitAsyncSearchRequest
+{
+   ...
+   public Elastic.Clients.Elasticsearch.KnnQuery? Knn { get; set; }
+   ...
+}
+----
+
+[source,csharp]
+----
+public sealed partial class MultisearchBody
+{
+   ...
+   public Elastic.Clients.Elasticsearch.KnnQuery? Knn { get; set; }
+   ...
+}
+----
+
+*_After_*
+
+[source,csharp]
+----
+public sealed partial class SubmitAsyncSearchRequest
+{
+   ...
+   public ICollection<Elastic.Clients.Elasticsearch.KnnQuery>? Knn { get; set; }
+   ...
+}
+----
+
+[source,csharp]
+----
+public sealed partial class MultisearchBody
+{
+   ...
+   public ICollection<Elastic.Clients.Elasticsearch.KnnQuery>? Knn { get; set; }
+   ...
+}
+----

docs/release-notes/release-notes.asciidoc

@@ -6,6 +6,7 @@
 [discrete]
 == Version 8.1
 
+* <<release-notes-8.1.1,Release notes v8.1.1>>
 * <<release-notes-8.1.0,Release notes v8.1.0>>
 
 [discrete]
@@ -24,6 +25,7 @@
 * <<release-notes-8.0.0,Release notes v8.0.0>>
 
 include::breaking-change-policy.asciidoc[]
+include::release-notes-8.1.1.asciidoc[]
 include::release-notes-8.1.0.asciidoc[]
 include::release-notes-8.0.10.asciidoc[]
 include::release-notes-8.0.9.asciidoc[]