Bump the pip group across 1 directory with 2 updates

Bumps the pip group with 2 updates in the /requirements directory: [onnx](https://github.com/onnx/onnx) and [opencv-python](https://github.com/opencv/opencv-python).


Updates `onnx` from 1.15.0 to 1.16.0
- [Release notes](https://github.com/onnx/onnx/releases)
- [Changelog](https://github.com/onnx/onnx/blob/main/docs/Changelog-ml.md)
- [Commits](onnx/onnx@v1.15.0...v1.16.0)

Updates `opencv-python` from 4.7.0.68 to 4.8.1.78
- [Release notes](https://github.com/opencv/opencv-python/releases)
- [Commits](https://github.com/opencv/opencv-python/commits)

---
updated-dependencies:
- dependency-name: onnx
  dependency-type: direct:production
  dependency-group: pip
- dependency-name: opencv-python
  dependency-type: direct:production
  dependency-group: pip
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements/server.txt

@@ -1,3 +1,3 @@
-onnx==1.15.0
+onnx==1.16.0
 onnxruntime==1.16.3
-opencv-python==4.7.0.68
+opencv-python==4.8.1.78