Update pytest requirement from ^6.2.4 to ^7.0.1

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@6.2.4...7.0.1)

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

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

pyproject.toml

@@ -33,7 +33,7 @@ python = "^3.6.2"
 anyio = "^3.4.0"
 
 [tool.poetry.dev-dependencies]
-pytest = "^6.2.4"
+pytest = "^7.0.1"
 mypy = "^0.930"
 flake8 = "^4.0.1"
 black = {version = "^21.5-beta.1", python = "^3.7"}