Enable weekly cron job (#720)

* Enable weekly cron job

* Update .github/workflows/pytest.yml

Co-authored-by: Matthias Feurer <lists@matthiasfeurer.de>

Co-authored-by: Matthias Feurer <lists@matthiasfeurer.de>

.github/workflows/pytest.yml

@@ -1,6 +1,11 @@
 name: Tests
 
-on: [push, pull_request]
+on:
+  push:
+  pull_request:
+  schedule:
+    # Every Monday at 7AM UTC
+    - cron: '0 07 * * 1'
 
 jobs:
   ubuntu:
@@ -23,6 +28,9 @@ jobs:
     - uses: actions/checkout@v2
     - name: Setup Python ${{ matrix.python-version }}
       uses: actions/setup-python@v2
+      # A note on checkout: When checking out the repository that
+      # triggered a workflow, this defaults to the reference or SHA for that event.
+      # Otherwise, uses the default branch (master) is used.
       with:
         python-version: ${{ matrix.python-version }}
     - name: Conda Install test dependencies