add for clause to cert alert

rules/http_healthcheck.yaml

@@ -23,8 +23,9 @@ groups:
 
     - alert: CertificateExpiration
       expr: ((probe_ssl_earliest_cert_expiry{instance=~"https://.*"} - time()) / 86400) < 7
+      for: 5m
       labels:
         severity: warning
       annotations:
         summary: Certificate will expire soon
-        description: The certicate at {{ $labels.instance }} will expire in {{ $value }} days.
+        description: The certicate at {{ $labels.instance }} will expire in {{ $value }} days.