Tweak github actions

Author: Kirill888

.github/workflows/pythonpackage.yml

@@ -16,45 +16,46 @@ jobs:
   build:
 
     runs-on: ubuntu-latest
-    strategy:
-      max-parallel: 2
-      matrix:
-        python-version: [3.6, 3.7]
-
     steps:
     - uses: actions/checkout@v1
+
     - name: Set up Python
       uses: actions/setup-python@v1
       with:
-        python-version: ${{ matrix.python-version }}
+        python-version: '3.8'
+
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install -r requirements.txt
+        pip install flake8 wheel twine
+
     - name: Lint with flake8
       run: |
         pip install flake8
         # stop the build if there are Python syntax errors or undefined names
         flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
         # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
         flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+
     - name: Package wheel
       run: |
         pip install wheel
         python setup.py bdist_wheel
         find dist -name "*whl" -exec unzip -l '{}' \;
+
     - name: Package source distribution
       run: |
         python setup.py sdist
+
     - name: Check Distribution Files
       run: |
-        pip install twine
         twine check dist/*
 
     - name: Publish (test pypi)
       if: |
         github.event_name == 'push' && (
           github.ref == 'refs/heads/develop'
+          || github.ref == 'refs/heads/prep-release'
         )
 
       run: |