Renovate: dependency pytest-cov to v6

pixl_core/pyproject.toml

@@ -33,7 +33,7 @@ test = [
     "pytest==8.3.2",
     "pytest-asyncio==0.24.0",
     "pytest-check==2.3.1",
-    "pytest-cov==5.0.0",
+    "pytest-cov==6.0.0",
     "pytest-pixl==0.2.0rc0",
     "xnat4tests==0.3.11",
 ]