Classifiers: Remove python 3.6

Author: tony

pyproject.toml

@@ -16,7 +16,6 @@ classifiers = [
   "Operating System :: MacOS :: MacOS X",
   "Programming Language :: Python",
   "Programming Language :: Python :: 3",
-  "Programming Language :: Python :: 3.6",
   "Programming Language :: Python :: 3.7",
   "Programming Language :: Python :: 3.8",
   "Programming Language :: Python :: 3.9",