Add project URLs

Author: liZe

setup.cfg

@@ -31,6 +31,11 @@ classifiers =
   Programming Language :: Python :: 3.6
   Programming Language :: Python :: 3.7
   Topic :: Multimedia :: Graphics :: Graphics Conversion
+project_urls =
+  Documentation = https://cairosvg.org/documentation/
+  Code = https://github.com/Kozea/CairoSVG/
+  Issue tracker = https://github.com/Kozea/CairoSVG/issues
+  Donation = https://www.patreon.com/kozea
 
 [options]
 packages = cairosvg