Remove Github action until 3.0

.github/workflows/lint.yml

@@ -1,30 +0,0 @@
-# This workflow will install Python dependencies, run tests and lint with a single version of Python
-# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
-
-name: CTFd CI
-
-on: [push]
-
-jobs:
-  build:
-
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        python-version: ['3.6']
-
-    name: Python ${{ matrix.python-version }}
-    steps:
-      - uses: actions/checkout@v2
-      - name: Setup python
-        uses: actions/setup-python@v1
-        with:
-          python-version: ${{ matrix.python-version }}
-          architecture: x64
-      - name: Install dependencies
-        run: |
-            python -m pip install --upgrade pip
-            pip install -r development.txt
-      - name: Lint
-        run: |
-            make lint