ci: Add coverage analysis via coveralls.io

Author: kadler

.github/workflows/build.yml

@@ -37,3 +37,7 @@ jobs:
         poetry install
     - name: Run tests
       run: python -m pytest tests
+    - name: Report coverage
+      env:
+        COVERALLS_REPO_TOKEN: ${{ secrets.COVERALLS_REPO_TOKEN }}
+      run: python -m coveralls

pyproject.toml

@@ -47,6 +47,10 @@ coverage = [
     { version = ">=6.3.0", python = ">=3.7" },
     { version = ">=4.5.4", python = "<3.7" },
 ]
+coveralls = [
+    { version = ">=3.3.0", python = ">=3.5" },
+    { version = "<2", python = "<3.5" },
+]
 pytest-cov = "~2.8"
 flake8 = ">=3.6.0"
 mock = "^3.0.5"