update version to 4.0.3.beta

Author: artemp

pyproject.toml

@@ -7,7 +7,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "mapnik"
-version = "4.0.0.beta"
+version = "4.0.3.beta"
 description = "Python bindings for Mapnik"
 license = { text = "GNU LESSER GENERAL PUBLIC LICENSE"}
 keywords = ["mapnik", "beautiful maps", "cartography", "python-mapnik"]