Change python version to 3.7

Also cache the requirements. And run tests before making the .egg file.

.github/workflows/deploy.yml

@@ -11,15 +11,30 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Python 3.6
+    - name: Set up Python 3.7
       uses: actions/setup-python@v2
       with:
-        python-version: 3.6
+        python-version: 3.7
+
+    - name: cache pip
+    - uses: actions/cache@v2
+      with:
+        path: ~/.cache/pip
+        key: ${{ runner.os }}-pip-${{ hashFiles('requirements.txt') }}
+        restore-keys: |
+          ${{ runner.os }}-pip-
+          ${{ runner.os }}-
+
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-      
+
+    - name: Test with Pytest
+      run: |
+        pip install pytest pytest-cov
+        py.test
+
     - name: Generate .egg
       run: python setup.py bdist_egg