test: include plotting dependency in dev extra

Author: yyyyyt123

pyproject.toml

@@ -60,6 +60,7 @@ dev = [
     "pytest>=6.0.0",
     "pytest-asyncio>=0.21.0",
     "pytest-cov>=4.1.0",
+    "matplotlib>=3.8.0",
     "black>=24.0.0",
     "ruff>=0.4.0",
     "isort>=5.13.0",