Bump onnxruntime-gpu in /rastervision_pytorch_learner

Bumps [onnxruntime-gpu](https://github.com/microsoft/onnxruntime) from 1.15.0 to 1.16.3.
- [Release notes](https://github.com/microsoft/onnxruntime/releases)
- [Changelog](https://github.com/microsoft/onnxruntime/blob/main/docs/ReleaseManagement.md)
- [Commits](microsoft/onnxruntime@v1.15.0...v1.16.3)

---
updated-dependencies:
- dependency-name: onnxruntime-gpu
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

rastervision_pytorch_learner/requirements.txt

@@ -14,4 +14,4 @@ opencv-python-headless==4.6.0.66
 matplotlib==3.7.1
 tqdm==4.65.0
 onnx==1.14.0
-onnxruntime-gpu==1.15.0
+onnxruntime-gpu==1.16.3