Update unasync requirement from ^0.5.0 to ^0.6.0 (#621)

Updates the requirements on [unasync](https://github.com/python-trio/unasync) to permit the latest version.
- [Release notes](https://github.com/python-trio/unasync/releases)
- [Commits](python-trio/unasync@v0.5.0...v0.6.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Steve Lorello <[email protected]>

Author: dependabot[bot]

pyproject.toml

@@ -57,7 +57,7 @@ bandit = "^1.7.4"
 coverage = "^7.1"
 pytest-cov = "^4.0.0"
 pytest-xdist = "^3.1.0"
-unasync = "^0.5.0"
+unasync = "^0.6.0"
 pytest-asyncio = "^0.23.5"
 email-validator = "^2.0.0"
 tox = "^4.14.1"