docs: note that active-queries (#26) and async-queries (#27) are not part of v0.4.0

Author: krinart

docs/release_notes/v0.4.0.md

@@ -96,6 +96,15 @@ Any option left unset falls back to the dataset's configured value. Applies to d
 Added:
 - `System.Text.Json` 9.0.9 (netstandard2.0 target only)
 
+## Release status
+
+**Not included in this release:**
+
+- [#26](https://github.com/spiceai/spice-dotnet/pull/26) — `ListActiveQueriesAsync`/`CancelActiveQueryAsync`
+- [#27](https://github.com/spiceai/spice-dotnet/pull/27) — async query submission over Flight `DoAction` (this PR also renames the synchronous `Query`/`QueryWithParams` to `Sql`/`SqlWithParamsAsync` — a breaking change)
+
+Both are implemented but will not be merged for v0.4.0. Note that #27, if it lands in a future release as currently written, would make that release breaking — v0.4.0 itself has none.
+
 ## Breaking Changes
 
 None.