Update ownership.yaml (#18762)

ownership.yaml

@@ -14,10 +14,10 @@ ownership:
     dependencies: []
     sev1:
       pagerduty: https://github.pagerduty.com/escalation_policies#PN57VQ1
-      tta: 30 min
+      tta: '30 min'
     sev2:
       issue: https://github.com/github/docs-internal/issues
-      tta: 5 business days
+      tta: '1 business day'
     sev3:
       slack: docs-engineering
-      tta: 30 min
+      tta: '1 week'