Drop support for Python 3.6.

Author: greschd

.github/workflows/ci.yml

@@ -82,7 +82,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8]
+        python-version: [3.7, 3.8]
         install-type: [dev]
         include:
         - python-version: 3.8

.github/workflows_source/ci.yml

@@ -72,7 +72,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8]
+        python-version: [3.7, 3.8]
         install-type: [dev]
         include:
           - python-version: 3.8

.pre-commit-config.yaml

@@ -1,9 +1,9 @@
 repos:
   - repo: https://github.com/asottile/pyupgrade
-    rev: v2.7.2
+    rev: v2.11.0
     hooks:
       - id: pyupgrade
-        args: [--py36-plus]
+        args: [--py37-plus]
 
   - repo: https://github.com/psf/black
     rev: 20.8b1

setup.cfg

@@ -19,15 +19,14 @@ classifiers =
     Natural Language :: English
     Operating System :: Unix
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Intended Audience :: Science/Research
     Topic :: Scientific/Engineering :: Physics
 
 [options]
-python_requires = >=3.6
+python_requires = >=3.7
 setup_requires =
     fastentrypoints
 install_requires =