Update development status to 'Production/Stable'

Author: JonasVautherin

setup.py

@@ -125,7 +125,7 @@ def version():
     cmdclass={'build': custom_build},
 
     classifiers=[
-        "Development Status :: 3 - Alpha",
+        "Development Status :: 5 - Production/Stable",
         "Intended Audience :: Developers",
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python :: 3.6",