[info.json] Add Python 3.9

Author: mpsonntag

odml/info.json

@@ -11,6 +11,7 @@
     "Programming Language :: Python :: 3.6",
     "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
     "Topic :: Scientific/Engineering",
     "Intended Audience :: Science/Research",
     "License :: OSI Approved :: BSD License"