update: update pytest-asyncio requirement from ~=0.21.0 to ~=0.21.1

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@v0.21.0...v0.21.1)

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

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

requirements_dev.txt

@@ -3,7 +3,7 @@ aioresponses~=0.7.4
 freezegun~=1.2.2
 parsedatetime~=2.6
 pylint~=2.17.4
-pytest-asyncio~=0.21.0
+pytest-asyncio~=0.21.1
 pytest-cov~=4.1.0
 pytest-mock~=3.11.1
 pytest-subprocess~=1.5.0