Fix python 3.6.

.github/workflows/pythontest.yml

@@ -13,7 +13,7 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         python-version:
-          ["3.7", "3.8", "3.9", "3.10", "3.11", pypy3]
+          ["3.7", "3.8", "3.9", "3.10", "3.11", "pypy3.9"]
         exclude:
           # sqlite3 exit handling seems to get in the way
           - os: macos-latest

setup.cfg

@@ -14,7 +14,6 @@ keywords = vcs, git
 classifiers =
     Development Status :: 4 - Beta
     License :: OSI Approved :: Apache Software License
-    Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9