Bump onnx from 1.12.0 to 1.14.0 in /src/frontends/onnx/tests

Bumps [onnx](https://github.com/onnx/onnx) from 1.12.0 to 1.14.0.
- [Release notes](https://github.com/onnx/onnx/releases)
- [Changelog](https://github.com/onnx/onnx/blob/main/docs/Changelog.md)
- [Commits](https://github.com/onnx/onnx/commits)

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

Signed-off-by: dependabot[bot] <support@github.com>

src/frontends/onnx/tests/requirements.txt

@@ -1,4 +1,4 @@
 # ONNX - generate test models
 docopt~=0.6.2
-onnx==1.12.0
+onnx==1.14.0
 protobuf>=3.18.1,<4.0.0