Experimental Changes to runner configuration - grow understanding on runner cron issues.

Production Change - Criticality 3 C3

Change Objective	Describe the objective of the change
Change Type	Configuration changes to shared runners on GitLab.com
Services Impacted	GitLab.com CI services - Shared Runners
Change Team Members	@dawsmith, @ahanselka , @erushton
Change Severity	C3
Buddy check or tested in staging	A colleague will review the change
Schedule of the change	Date and time (with timezone)
Duration of the change	Time to execute the change ( including a possible rollback )
Detailed steps for the change. Each step must include:	- pre-conditions for execution of the step, - execution commands for the step, - post-execution validation for the step , - rollback of the step

Details on changes coming - we need to coordinate with @erushton to pick the values and times we want to test these changes.

Test 1: Adjust warm pool for shared runner managers

- https://ops.gitlab.net/gitlab-cookbooks/chef-repo/merge_requests/1784
- To revert, revert the MR and run chef-client on SRM machines

Test 2: Adjust cron schedule for pipeline_schedule_worker from '19 * * * *'

- https://ops.gitlab.net/gitlab-cookbooks/chef-repo/merge_requests/1806
- To revert, revert the MR, apply it to chef, and run `chef-client` on the SRM machines.