Bump pytest-asyncio from 0.11.0 to 0.12.0

Bumps [pytest-asyncio](https://github.com/pytest-dev/pytest-asyncio) from 0.11.0 to 0.12.0.
- [Release notes](https://github.com/pytest-dev/pytest-asyncio/releases)
- [Commits](pytest-dev/pytest-asyncio@v0.11.0...v0.12.0)

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

requirements-dev.txt

@@ -1,5 +1,5 @@
 pre-commit==2.3.0
 pytest==5.4.1
-pytest-asyncio==0.11.0
+pytest-asyncio==0.12.0
 sphinx==3.0.3
 sphinx_rtd_theme==0.4.3