Drop support for older Python & Django

With the exception of Python 3.7 these are all beyond end of life
already and make it harder to support newer Python & Django.

Author: PeterJCLaw

.github/workflows/check.yml

@@ -6,19 +6,12 @@ on:
 jobs:
   test:
     name: Test
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     strategy:
       matrix:
-        python-version: ["3.6", "3.7", "3.8", "3.9"]
-        django-version: ["2.2", "3.0", "3.1", "3.2", "4.0"]
-        exclude:
-          # Python 3.6 is not supported beyond Django 3.2
-          - python-version: "3.6"
-            django-version: "4.0"
-          # Python 3.7 is not supported beyond Django 3.2
-          - python-version: "3.7"
-            django-version: "4.0"
+        python-version: ["3.8", "3.9"]
+        django-version: ["3.2", "4.0"]
 
     steps:
       - name: Checkout
@@ -44,16 +37,12 @@ jobs:
 
   lint:
     name: Lint
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     strategy:
       matrix:
-        python-version: ["3.6", "3.9"]
-        django-version: ["2.2", "4.0"]
-        exclude:
-          # Python 3.6 is not supported beyond Django 3.2
-          - python-version: "3.6"
-            django-version: "4.0"
+        python-version: ["3.8", "3.9"]
+        django-version: ["3.2", "4.0"]
 
     steps:
       - name: Checkout
@@ -79,16 +68,12 @@ jobs:
 
   type-check:
     name: Type Check
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
 
     strategy:
       matrix:
-        python-version: ["3.6", "3.9"]
-        django-version: ["2.2", "4.0"]
-        exclude:
-          # Python 3.6 is not supported beyond Django 3.2
-          - python-version: "3.6"
-            django-version: "4.0"
+        python-version: ["3.8", "3.9"]
+        django-version: ["3.2", "4.0"]
 
     steps:
       - name: Checkout

.github/workflows/publish.yml

@@ -24,7 +24,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v4
         with:
-          python-version: '3.7'
+          python-version: '3.9'
           cache: poetry
 
       - name: Build

poetry.lock

@@ -14,8 +14,8 @@ classifiers = [
 ]
 
 [tool.poetry.dependencies]
-python = ">=3.6.1,<4"
-django = ">=2.2"
+python = ">=3.8,<4"
+django = ">=3.2"
 daemonize = "~=2.5.0"
 prometheus-client = "~=0.7"
 typing-extensions = "^4"