Add Python 3.8 to build matrix (#58)

* Add Python 3.8 to build matrix

* Force pipenv to use matrix Python  version

* Put release step in separate job

* Fix build.yml workflow

.github/workflows/build.yml

@@ -3,12 +3,12 @@ name: Build
 on: [push, pull_request]
 
 jobs:
-  build:
 
+  test:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python_version: [3.7]
+        python_version: [3.7, 3.8]
 
     services:
       mongo:
@@ -18,22 +18,37 @@ jobs:
 
     steps:
     - uses: actions/checkout@v1
-    - name: Set up Python 3.7
+    - name: Set up Python
       uses: actions/setup-python@v1
       with:
         python-version: ${{ matrix.python_version }}
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pipenv
-        pipenv install --dev
+        pipenv install --python ${{ matrix.python_version }} --dev
     - name: Test with pytest
       env:
         CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
       run: |
         pipenv run pytest --cov=fastapi_users/
         pipenv run codecov
-    - name: Release on PyPI
+
+  release:
+    runs-on: ubuntu-latest
+    needs: test
     if: startsWith(github.ref, 'refs/tags/')
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up Python
+      uses: actions/setup-python@v1
+      with:
+        python-version: 3.7
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pipenv
+        pipenv install --dev
+    - name: Release on PyPI
       env:
         FLIT_USERNAME: ${{ secrets.FLIT_USERNAME }}
         FLIT_PASSWORD: ${{ secrets.FLIT_PASSWORD }}