fix(deps): update dependency graphviz to >=0.16,<0.21

pyproject.toml

@@ -52,7 +52,7 @@ duckdb-engine = { version = ">=0.1.8,<0.2.0", optional = true }
 fsspec = { version = ">=2022.1.0", optional = true }
 GeoAlchemy2 = { version = ">=0.6.3,<0.12", optional = true }
 geopandas = { version = ">=0.6,<0.11", optional = true }
-graphviz = { version = ">=0.16,<0.20", optional = true }
+graphviz = { version = ">=0.16,<0.21", optional = true }
 impyla = { version = ">=0.17,<0.19", optional = true, extras = ["kerberos"] }
 lz4 = { version = ">=3.1.10,<5", optional = true }
 psycopg2 = { version = ">=2.8.4,<3", optional = true }