Fix test framework and python version

.github/workflows/selfhosted-action.yml

@@ -10,13 +10,14 @@ jobs:
 
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Python 3.7
+    - name: Set up Python 3.8
       uses: actions/setup-python@v2
       with:
-        python-version: 3.7
+        python-version: 3.8
     - name: Install dependencies
       run: |
-        pip install -r requirements.txt
-    - name: Test with unittest
+        pip install -e .
+        pip install pytest
+    - name: Test with pytest
       run: |
-        python -m unittest discover
+        pytest