add coveralls

.github/workflows/validate.yml

@@ -1,4 +1,4 @@
-name: Python package
+name: unit tests
 
 on: [push]
 
@@ -20,7 +20,11 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           pip install --upgrade tox
+          pip3 install --upgrade coveralls
           if [ -f requirements-dev.txt ]; then pip install -r requirements-dev.txt; fi
       - name: Test with tox
         run: |
-          tox -e py
+          tox -e py
+      - name: Publish test results
+        run: |
+          coveralls