Update the GitHub build schedule to every Sunday

[marionbarker]

Purpose

Our previous attempt to build on the second Saturday of the month was configured to build every Saturday and on the 8-14th day of the month.

While doing this PR to fix the logic, also fix the name, run-name from Loop Follow to LoopFollow. That change will be for LoopFollow only. The other apps will need similar changes to modify the build schedule.

Update the build_xxx.yml logic.

Change the schedule to run at a specific time every Sunday:

• modify the logic to build monthly (2nd Sunday) regardless of status
• keep the logic to build weekly if there are new commits to the code

This new method eliminates one build process per month. The monthly build starts at the same time as the weekly check for updates.

The once a month logic is much simpler

• add a new job day_in_month that determines if this is the second time this day of the week has happened in this month
• the output IS_SECOND_IN_MONTH is used to decide whether to skip or execute a build

[marionbarker]

Test

Please ignore the many commits - this will be a squash and merge commit.

Tests succeeded.

Test that it does not trigger on days that are not desired

The bb_schedule branch was pushed to the docs-test GitHub org, which had previously built on Oct 8.

• ✅ Success is that it did not trigger on Oct 9

Test that schedule build happens with new logic

Make a test branch, trigger_test in which the only change from bb_schedule is

-    - cron: "17 10 * * 0" # Sunday at UTC 10:17
+    - cron: "mm hh * * 5" # Friday at UTC hh:mm for trigger test

where the hh:mm was updated throughout the day (Friday) as we did testing. (Thanks to @bjorkert for his DM finding typos and making suggestions.)

Push trigger_test to docs-test GitHub org and make it the default branch.

Finally got the syntax correct. Then go back and clean up the code.

Tests with final syntax

Success:

• ✅ Modify only the trigger time as indicated above
  • show the Build is triggered as expected: Build Loop Follow (trigger_test)
• ✅ Modify the trigger time as indicated above and change the logic to look for the 3rd week instead of the 2nd week
  • show the Build is skipped as expected: Build LoopFollow (trigger_test)