Add PEP440 verion names

Author: codingjoe

.github/workflows/ci.yml

@@ -53,9 +53,9 @@ jobs:
           - "3.9"
           - "3.10"
         django-version:
-          - "2.2"
-          - "3.2"
-          - "4.0"
+          - "2.2a"
+          - "3.2a"
+          - "4.0a"
     steps:
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2
@@ -70,7 +70,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip setuptools wheel codecov
         python -m pip install -e .[dramatiq]
-        python -m pip install django==${{ matrix.django-version }}
+        python -m pip install django~=${{ matrix.django-version }}
     - name: Run tests
       run: python setup.py test
     - run: codecov