Bump from alpha to beta

Author: pganssle

setup.cfg

@@ -12,7 +12,7 @@ url = https://github.com/python/tzdata
 author = Python Software Foundation
 author_email = paul@ganssle.io
 classifiers =
-    Development Status :: 3 - Alpha
+    Development Status :: 4 - Beta
     Intended Audience :: Developers
     License :: OSI Approved :: Apache Software License
     Programming Language :: Python :: 2