build: Upgrade Python version

.github/workflows/pythonapp.yml

@@ -8,10 +8,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v1
-    - name: Set up Python 3.7
+    - name: Set up Python
       uses: actions/setup-python@v1
       with:
-        python-version: 3.7
+        python-version: 3.8
     - name: Install dependencies
       run: |
         pip install --upgrade pip pipenv

Pipfile

@@ -13,4 +13,4 @@ tabulate = "*"
 numpy = ">=1.17.0,<2.0.0"
 
 [requires]
-python_version = "3.7"
+python_version = "3.8"