Fix py.test in CI

.github/workflows/build.yml

@@ -23,7 +23,7 @@ jobs:
     - name: Install
       run: |
         python -m pip install --upgrade pip
-        pip install pytest mock pycodestyle coverage pylint
+        pip install pytest pytest-cov mock pycodestyle coverage pylint
         pip install -e .
 
     - name: Lint
@@ -33,5 +33,4 @@ jobs:
 
     - name: Test with pytest
       run: |
-        coverage run --source amodem/ --omit="*/__main__.py" -m py.test -v
-        coverage report
+        py.test -v --cov=amodem