chore: refine classifiers in setup.py

Author: reata

README.md

@@ -4,3 +4,5 @@ SQL Lineage Analysis Tool powered by Python
 [![Build Status](https://travis-ci.org/reata/sqllineage.svg?branch=master)](https://travis-ci.org/reata/sqllineage)
 [![codecov](https://codecov.io/gh/reata/sqllineage/branch/master/graph/badge.svg)](https://codecov.io/gh/reata/sqllineage)
 [![Documentation Status](https://readthedocs.org/projects/sqllineage/badge/?version=latest)](https://sqllineage.readthedocs.io/en/latest/?badge=latest)
+
+This project is still in Alpha stage. Interfaces are supposed to change in upcoming development cycles.

setup.py

@@ -16,9 +16,14 @@
     url="https://github.com/reata/sqllineage",
     packages=setuptools.find_packages(exclude=("tests",)),
     classifiers=[
-        "Programming Language :: Python :: 3",
+        "Development Status :: 3 - Alpha",
         "License :: OSI Approved :: MIT License",
         "Operating System :: OS Independent",
+        "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.5",
+        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: Implementation :: CPython"
     ],
     python_requires=">=3.5",
     install_requires=[