Update Django and Python version support

Author: codingjoe

.github/workflows/tests.yml

@@ -9,8 +9,13 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [3.5, 3.6, 3.7]
-        django-version: [1.11.*, 2.2.*]
+        python-version:
+          - "3.7"
+          - "3.8"
+          - "3.9"
+        django-version:
+          - "2.2"
+          - "3.1"
 
     steps:
     - uses: actions/checkout@v1
@@ -21,7 +26,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip setuptools
-        pip install django==${{ matrix.django-version }}
+        pip install django~=${{ matrix.django-version }}
     - name: Test with pytest
       run: python setup.py test
     - name: Codecov

setup.cfg

@@ -26,7 +26,7 @@ classifier =
 include_package_data = True
 packages = stdimage
 install_requires =
-    Django>=1.11
+    Django>=2.2
     pillow>=2.5
     progressbar2>=3.0.0
 setup_requires =