Adds Codecov

.github/workflows/build.yml

@@ -37,6 +37,12 @@ jobs:
       - name: Run tests
         run: uv run poe tests
 
+      - name: Upload coverage reports to Codecov
+        uses: codecov/codecov-action@v5
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+        if: matrix.python-version == '3.10'
+
   publish:
     name: publish
     runs-on: ubuntu-latest