Setup Codecov uploading and reporting (#124)

* Enable Codecov uploading and reporting on CI
* Remove Codecov terminal output

.github/codecov.yml

@@ -0,0 +1,14 @@
+coverage:
+  precision: 1
+  status:
+    project:
+      default:
+        informational: true
+    patch:
+      default:
+        informational: true
+
+comment:
+  require_changes: true
+  # Don't display the large graph
+  layout: "diff, files"

.github/workflows/pytest.yaml

@@ -129,7 +129,16 @@ jobs:
       - name: Run tests
         run: |
           source .venv/bin/activate
-          pytest --backend ${{ matrix.backend }} --postgres-dsn "postgresql://postgres:postgres@localhost:5432/test" --cov-report xml:.coverage.xml --cov-report term --cov=ixmp4 -rsxX --benchmark-skip --color=yes
+          pytest --backend ${{ matrix.backend }} --postgres-dsn "postgresql://postgres:postgres@localhost:5432/test" --cov-report xml:.coverage.xml --cov=ixmp4 -rsxX --benchmark-skip --color=yes
+
+      #------------------------------
+      #  Upload coverage to codecov
+      #------------------------------
+      - name: Upload results to Codecov
+        uses: codecov/codecov-action@v4
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          files: .coverage.xml
 
   pre-commit:
     name: Code quality