Actually fix Github CI for Python 3.5

Previous commit didn't make it.

See actions/setup-python#866

.github/workflows/tests.yml

@@ -6,6 +6,10 @@ on:
  schedule:
  - cron: 0 0 * * 0
 
+# Temporary workaround for https://github.com/actions/setup-python/issues/866
+env:
+ PIP_TRUSTED_HOST: pypi.python.org pypi.org files.pythonhosted.org
+
 jobs:
  tests:
  if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.repository
@@ -27,8 +31,6 @@ jobs:
  include:
  - os: ubuntu-20.04
  python-version: '3.5'
- # Temporary fix for https://github.com/actions/setup-python/issues/866
- env: PIP_TRUSTED_HOST="pypi.python.org pypi.org files.pythonhosted.org"
  - os: ubuntu-20.04
  python-version: '3.6'
  - os: windows-2022