feat(ci): use pyproject.toml instead of requirements.txt

Author: chaimleib

.github/workflows/build.yml

@@ -46,8 +46,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install flake8 pytest pytest-cov sortedcontainers
-        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+        if [ -f pyproject.toml ]; then pip install flake8 '.[test]'; fi
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names