removed coretk specific github action

.github/workflows/coretk-checks.yml

@@ -1,35 +0,0 @@
-name: CORE Tk Checks
-
-on: [push]
-
-jobs:
-  build:
-    runs-on: ubuntu-18.04
-    steps:
-      - uses: actions/checkout@v1
-      - name: Set up Python 3.7
-        uses: actions/setup-python@v1
-        with:
-          python-version: 3.7
-      - name: Install pipenv
-        run: |
-          python -m pip install --upgrade pip
-          pip install pipenv
-          cd daemon
-          cp setup.py.in setup.py
-          cp core/constants.py.in core/constants.py
-          sed -i 's/True/False/g' core/constants.py
-          cd ../coretk
-          pipenv install --dev
-      - name: isort
-        run: |
-          cd coretk
-          pipenv run isort -c
-      - name: black
-        run: |
-          cd coretk
-          pipenv run black --check .
-      - name: flake8
-        run: |
-          cd coretk
-          pipenv run flake8