feat(tests): add pytest-cov to dependencies for test coverage reporting

Author: tumf

pyproject.toml

@@ -21,6 +21,7 @@ test = [
     "pytest>=8.3.4",
     "pytest-asyncio>=0.24.0",
     "pytest-env>=1.1.0",
+    "pytest-cov>=6.0.0",
 ]
 dev = [
     "ruff>=0.0.262",