chore(deps): update dependency pytest-cov to v6

requirements/dev.txt

@@ -12,7 +12,7 @@ mkdocs==1.6.1
 mkdocstrings[python]==0.27.0
 psycopg[binary]==3.2.3
 pytest==8.3.4
-pytest-cov==5.0.0
+pytest-cov==6.0.0
 pytest-django==4.9.0
 pytest-factoryboy==2.7.0
 pytest-mock==3.14.0