Update dependencies for Python 3.11 compatibility

Critical updates:
- pytest: 6.2.5 → 7.4.3 (Python 3.11 support)
- pytest-asyncio: 0.16.0 → 0.21.1 (fixes Python 3.11 async issues)
- pytest-cov: 3.0.0 → 4.1.0
- anyio: 3.7.1 (better async/await support)
- attrs: 23.1.0
- pluggy: 1.3.0
- Remove atomicwrites (deprecated, causes Python 3.11 issues)
- Remove py package (deprecated)
- Make tomli conditional for Python < 3.11 (3.11+ has built-in tomllib)

The old pytest-asyncio 0.16.0 is the main culprit - it has known
compatibility issues with Python 3.11's improved async implementation.

Author: Johannes Lichtenberger

requirements-all.txt

@@ -1,7 +1,6 @@
 alabaster==0.7.12
-anyio==3.3.4
-atomicwrites==1.4.0
-attrs==21.2.0
+anyio==3.7.1
+attrs==23.1.0
 Babel==2.9.1
 certifi==2022.12.7
 charset-normalizer==2.0.7
@@ -17,13 +16,12 @@ iniconfig==1.1.1
 Jinja2==3.1.4
 MarkupSafe==2.0.1
 packaging==21.2
-pluggy==1.0.0
-py==1.11.0
+pluggy==1.3.0
 Pygments==2.15.0
 pyparsing==2.4.7
-pytest==6.2.5
-pytest-asyncio==0.16.0
-pytest-cov==3.0.0
+pytest==7.4.3
+pytest-asyncio==0.21.1
+pytest-cov==4.1.0
 pytz==2021.3
 requests==2.31.0
 rfc3986==1.5.0
@@ -38,5 +36,5 @@ sphinxcontrib-jsmath==1.0.1
 sphinxcontrib-qthelp==1.0.3
 sphinxcontrib-serializinghtml==1.1.5
 toml==0.10.2
-tomli==1.2.2
+tomli==2.0.1; python_version < '3.11'
 urllib3==1.26.19