Added missing pip install coveralls in actions

Fix README

.github/workflows/actions.yml

@@ -21,6 +21,7 @@ jobs:
       - name: Install dependencies
         run: |
           pip install uv
+          uv pip install coveralls --system
           uv pip install '.[dev]' --system
       - name: mypy
         run: |

README.md

@@ -49,7 +49,7 @@ Our CI/CD pipeline produces a more comprehensive test report using `coverage` an
 
 ```sh
 uv pip install coverage coveralls
-python -m pytest --cov=src  tests
+python -m pytest --cov=src tests
 ```
 
 ### Run linting and auto-formatting