Add stable classifier

Author: BobDotCom

setup.py

@@ -104,7 +104,7 @@
     extras_require=extras_require,
     python_requires=">=3.8.0",
     classifiers=[
-        "Development Status :: 4 - Beta",
+        "Development Status :: 5 - Production/Stable",
         "License :: OSI Approved :: MIT License",
         "Intended Audience :: Developers",
         "Natural Language :: English",