Add support for Django 3.1 (#10)

No code changes required - just a change in classifiers and the CI test matrix.

.pre-commit-config.yaml

@@ -1,7 +1,7 @@
 repos:
     # python import sorting - will amend files
     - repo: https://github.com/pre-commit/mirrors-isort
-      rev: v5.0.4
+      rev: v5.4.2
       hooks:
           - id: isort
 
@@ -11,14 +11,6 @@ repos:
       hooks:
           - id: black
 
-    # PEP8 linting, with added Django goodness, and custom YJ plugin
-    - repo: https://github.com/pre-commit/mirrors-pylint
-      rev: v2.5.3
-      hooks:
-          - id: pylint
-            args:
-                - --rcfile=.pylintrc
-
     # Flake8 includes pyflakes, pycodestyle, mccabe, pydocstyle, bandit
     - repo: https://gitlab.com/pycqa/flake8
       rev: 3.8.3
@@ -40,11 +32,3 @@ repos:
                 - --ignore-missing-imports
                 - --follow-imports=silent
             exclude: ^tests
-
-    # JS, JSON and SCSS formatting
-    - repo: https://github.com/prettier/prettier
-      rev: 2.0.5
-      hooks:
-          - id: prettier
-            args:
-                - --config=.prettierrc

.travis.yml

@@ -1,6 +1,22 @@
 language: python
-python:
-    - "3.7"
-    - "3.8"
-install: pip install tox-travis
+
+os: linux
+
+dist: xenial
+
+install: pip install tox tox-travis
+
 script: tox
+
+jobs:
+    include:
+        - { python: "3.7", env: TOXENV=py37-django22, services: postgresql }
+        - { python: "3.7", env: TOXENV=py37-django30, services: postgresql }
+        - { python: "3.7", env: TOXENV=py37-django31 }
+        - { python: "3.8", env: TOXENV=py38-django22, services: postgresql }
+        - { python: "3.8", env: TOXENV=py38-django30, services: postgresql }
+        - { python: "3.8", env: TOXENV=py38-django31 }
+        - { python: "3.8", env: TOXENV=py38-djangomaster }
+        - { python: "3.8", env: TOXENV=fmt }
+        - { python: "3.8", env: TOXENV=lint }
+        - { python: "3.8", env: TOXENV=mypy }