Move Py compat target to 3.8 (closes gh-160)

Author: inducer

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
             uses: actions/setup-python@v4
             with:
                 # matches compat target in setup.py
-                python-version: '3.6'
+                python-version: '3.8'
         -   name: "Main Script"
             run: |
                 curl -L -O https://gitlab.tiker.net/inducer/ci-support/raw/main/prepare-and-run-flake8.sh
@@ -70,7 +70,7 @@ jobs:
         runs-on: ubuntu-latest
         strategy:
             matrix:
-                python-version: ["3.6", "3.8", "3.9", "3.x", "pypy3.8"]
+                python-version: ["3.8", "3.9", "3.x", "pypy3.8"]
         steps:
         -   uses: actions/checkout@v3
         -

setup.py

@@ -24,8 +24,6 @@
           "Natural Language :: English",
           "Programming Language :: Python",
           "Programming Language :: Python :: 3",
-          "Programming Language :: Python :: 3.6",
-          "Programming Language :: Python :: 3.7",
           "Topic :: Scientific/Engineering",
           "Topic :: Scientific/Engineering :: Information Analysis",
           "Topic :: Scientific/Engineering :: Mathematics",
@@ -34,11 +32,10 @@
           "Topic :: Utilities",
           ],
 
-      python_requires="~=3.6",
+      python_requires="~=3.8",
 
       install_requires=[
           "platformdirs>=2.2.0",
-          "dataclasses>=0.7;python_version<='3.6'",
           "typing_extensions>=4.0; python_version<'3.11'",
           ],