feat: remove unuseful flake8 (#7)

.github/workflows/flake8.yml

-name: PEP8 Check
-on:
-  push:
-    branches: [main]
-  pull_request:
-    branches: [main]
-jobs:
-  pep8:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - name: Set up Python 3.10
-        uses: actions/setup-python@v4
-        with:
-          python-version: '3.10'
-      - name: Install flake8
-        run: pip install flake8
-      - name: Run flake8
-        run: flake8 --ignore=E501 .