feat: update ci and README.md

Author: AtticusZeller

.github/workflows/ci.yml

@@ -30,8 +30,10 @@ jobs:
       - run: poetry install
       - run: poetry run pytest
 
-      - name: Upload Coverage
+      - name: Upload coverage reports to Codecov
         uses: codecov/codecov-action@v3
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
 
   semantic-release:
     name: Semantic Release and Publish