Add pytest-cov to produce coverage report

Author: 94929

.github/workflows/build.yml

@@ -19,9 +19,10 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install -r requirements.txt
+        pip install coveralls
     - name: Run unit tests
       run: |
-        python -m pytest
+        python -m pytest --cov=iamport tests
     - name: Run convention tests
       run: |
         python -m flake8 iamport tests --ignore E203,W503,W504

requirements.txt

@@ -1,6 +1,7 @@
 requests==2.26.0
 pytest==6.2.4
+pytest-cov==2.12.1
 flake8==3.9.2
 isort==5.9.3
 mypy==0.910
-types-requests==2.25.6
+types-requests==2.25.6