Enabling coveralls coverage

.github/workflows/ci.yml

@@ -73,6 +73,8 @@ jobs:
           coverage report
       - name: check formatting
         run: make black arg=--check
+      - name: Coveralls
+        uses: AndreMiras/coveralls-python-action@develop
       - name: run Codacy coverage reporter
         uses: codacy/codacy-coverage-reporter-action@master
         with:

README.rst

@@ -5,6 +5,8 @@
     :target: https://www.codacy.com/gh/bihealth/varfish-server/dashboard?utm_source=github.com&utm_medium=referral&utm_content=bihealth/varfish-server&utm_campaign=Badge_Grade
 .. image:: https://app.codacy.com/project/badge/Coverage/f47216cf5a4349acbb9baf5ca1c91329
     :target: https://www.codacy.com/gh/bihealth/varfish-server/dashboard?utm_source=github.com&utm_medium=referral&utm_content=bihealth/varfish-server&utm_campaign=Badge_Coverage
+.. image:: https://coveralls.io/repos/github/bihealth/varfish-server/badge.svg?branch=master
+    :target: https://coveralls.io/github/bihealth/varfish-server?branch=master
 .. image:: https://img.shields.io/badge/License-MIT-green.svg
     :target: https://opensource.org/licenses/MIT