add project_urls section to setup.py

Author: slayoo

setup.py

@@ -142,4 +142,9 @@ def build_extension(self, ext):  # pylint: disable=too-many-branches
     setup_requires=["setuptools_scm"],
     install_requires=['numpy'],
     license="GPL-3.0",
+    project_urls={
+        "Tracker": "https://github.com/open-atmos/PyPartMC/issues",
+        "Documentation": "https://open-atmos.github.io/PyPartMC",
+        "Source": "https://github.com/open-atmos/PyPartMC/",
+    }
 )