Fix broken "Tests" workflow

.github/workflows/pythonapp.yml

@@ -23,7 +23,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install -r requirements.txt
+        pip install .
     - name: Lint with flake8
       run: |
         pip install flake8

setup.py

@@ -31,7 +31,7 @@ setup(name='prototorch',
               'sklearn',
               'matplotlib',
           ],
-          'tests': ['unittest'],
+          'tests': ['pytest'],
       },
       classifiers=[
           'Development Status :: 2 - Pre-Alpha', 'Environment :: Console',