Update pytest-asyncio requirement from ~=0.15 to ~=0.16

Updates the requirements on [pytest-asyncio](https://github.com/pytest-dev/pytest-asyncio) to permit the latest version.
- [Release notes](https://github.com/pytest-dev/pytest-asyncio/releases)
- [Commits](pytest-dev/pytest-asyncio@v0.15.0...v0.16.0)

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

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

requirements-test.txt

@@ -6,7 +6,7 @@ pre-commit~=2.16
 pylint~=2.12
 pylint-strict-informational==0.1
 pytest~=6.2
-pytest-asyncio~=0.15
+pytest-asyncio~=0.16
 pytest-cov~=3.0
 requests-mock~=1.9
 flake8-docstrings~=1.6