Update pytest requirement from <7.5,>=5.0 to >=5.0,<8.1 in /tests

Updates the requirements on [pytest](https://github.com/pytest-dev/pytest) to permit the latest version.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/main/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@5.0.0...8.0.0)

---
updated-dependencies:
- dependency-name: pytest
  dependency-type: direct:production
...

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

tests/constraints.txt

@@ -18,7 +18,7 @@ opencv-python>=4.5
 paddlepaddle==2.5.0
 protobuf>=3.18.1,<4.0.0
 py>=1.9.0
-pytest>=5.0,<7.5
+pytest>=5.0,<8.1
 pytest-dependency==0.5.1
 pytest-html==4.1.1
 pytest-timeout==2.1.0