docs: Update testing files and DEVELOPMENT_MAINTENANCE.md
General MR
Summary
Updates DEVELOPMENT_MAINTENANCE.md to match updates made in other service mesh repos.
UNCLASSIFIED - NO CUI
ATTENTION: Immediate action is required to maintain compatibility with P1 services. Please visit https://p1notifications.dso.mil and see the "DSO.MIL Certificates Renewal" announcement under the "Notifications" section for more details.
UNCLASSIFIED - NO CUI