Update setup.py

Author: TomNicholas

setup.py

@@ -16,16 +16,17 @@
     name="datatree",
     description="Hierarchical tree-like data structures for xarray",
     long_description=long_description,
-    url="https://github.com/TomNicholas/datatree",
+    url="https://github.com/xarray-contrib/datatree",
     author="Thomas Nicholas",
     author_email="[email protected]",
     license="Apache",
     classifiers=[
-        "Development Status :: 5 - Production/Stable",
+        "Development Status :: 3 - Alpha",
         "Intended Audience :: Science/Research",
         "Topic :: Scientific/Engineering",
         "License :: OSI Approved :: Apache License",
         "Operating System :: OS Independent",
+        "Programming Language :: Python",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
     ],