Add trusted host workaround for tests workflow

Author: Vladyslav Tymofeiev

.github/workflows/playbook-test.yml

@@ -27,6 +27,8 @@ jobs:
       uses: actions/setup-python@v3
       with:
         python-version: ${{ matrix.python-version }}
+      env:
+        PIP_TRUSTED_HOST: "pypi.python.org pypi.org files.pythonhosted.org"
     - name: Install Dependencies
       run: |
         pip install demjson

.github/workflows/syntax-test.yml

@@ -27,6 +27,8 @@ jobs:
       uses: actions/setup-python@v3
       with:
         python-version: ${{ matrix.python-version }}
+      env:
+        PIP_TRUSTED_HOST: "pypi.python.org pypi.org files.pythonhosted.org"
     - name: Install Dependencies
       run: |
         pip install demjson