Add weekly Saturday morning build and prevent Python 3.11 from running on PRs (#1387)

* Add weekly Saturday morning build and prevent Python 3.11 from running on PRs
* Fix extraneous greater than symbol
* Add branches and paths to cron schedule
* Add back missing hyphen before cron
* Trying to fix YAML syntax error
* Remove branches and paths from schedule
* Fix invalid conditional, push 3.11 check down to actual tests like we did with 3.10
* Separate out PR tests and scheduled tests
* Fix YAML syntax
* Fix uses action reference
* Use proper action folder structure
* Check out repo before running local action
* Specify bash shell and remove unneeded if
* Specify shell for each run statement
* Move secret out of composite action since it is not supported directly
* Fix half-fixed previous commit
* Remove extraneous ./
* Fix pathing and name steps
* take out shell key from action
* put back missing git config line in workflows

Co-authored-by: Jonathan Wren <jonathan@nowandwren.com>

.github/workflows/testing_schedule.yaml

@@ -0,0 +1,25 @@
+name: Testing
+
+on:
+  schedule:
+    - cron: '0 0 * * SAT'
+
+defaults:
+  run:
+    shell: bash # needed to prevent Windows from using PowerShell
+
+jobs:
+  test_all:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: [ 3.7, 3.8, 3.9, '3.10', 3.11-dev ]
+        os: [ ubuntu-latest, macos-latest, windows-latest ]
+    steps:
+      - run: git config --global core.autocrlf false
+      - uses: actions/checkout@v2
+      - name: Run tests
+        uses: ./.github/actions/run_tests
+        with:
+          cache-string: ${{ secrets.CACHE_STRING }}