[camerax] Correct missing features list in README (#4123)

Updates README.md to accurately reflect unimplemented functionality.

packages/camera/camera_android_camerax/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.5.0+5
+
+* Updates `README.md` to fully cover unimplemented functionality.
+
 ## 0.5.0+4
 
 * Removes obsolete null checks on non-nullable values.

packages/camera/camera_android_camerax/README.md

@@ -49,6 +49,11 @@ Any specified `ResolutionPreset` wll go unused in favor of CameraX defaults and
 
 `setZoomLevel` is unimplemented.
 
+### Some video capture functionality \[[Issue #127896][127896], [Issue #126477][126477]\]
+
+`startVideoCapturing` is unimplemented; use `startVideoRecording` instead.
+`onVideoRecordedEvent` is also unimplemented.
+
 ## Contributing
 
 For more information on contributing to this plugin, see [`CONTRIBUTING.md`](CONTRIBUTING.md).
@@ -66,3 +71,5 @@ For more information on contributing to this plugin, see [`CONTRIBUTING.md`](CON
 [120468]: https://github.com/flutter/flutter/issues/120468
 [120467]: https://github.com/flutter/flutter/issues/120467
 [125371]: https://github.com/flutter/flutter/issues/125371
+[126477]: https://github.com/flutter/flutter/issues/126477
+[127896]: https://github.com/flutter/flutter/issues/127896

packages/camera/camera_android_camerax/pubspec.yaml

@@ -3,7 +3,7 @@ description: Android implementation of the camera plugin using the CameraX libra
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera_android_camerax
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
 
-version: 0.5.0+4
+version: 0.5.0+5
 
 environment:
   sdk: ">=2.19.0 <4.0.0"