alerts: change rate time

Prometheus documentation [1] uses 5m rate time ranges. This patch
makes our example consistent with documentation.

1. https://prometheus.io/docs/prometheus/latest/configuration/alerting_rules/

Author: DifferentialOrange

example_cluster/prometheus/alerts.yml

@@ -131,7 +131,7 @@ groups:
 
   # Alert for Tarantool high vinyl transactions conflict rate.
   - alert: HighVinylTxConflictRate
-    expr: rate(tnt_vinyl_tx_conflict[2m]) / rate(tnt_vinyl_tx_commit[2m]) > 0.05
+    expr: rate(tnt_vinyl_tx_conflict[5m]) / rate(tnt_vinyl_tx_commit[5m]) > 0.05
     for: 1m
     labels:
       severity: critical
@@ -142,7 +142,7 @@ groups:
 
   # Alert for Tarantool high vinyl scheduler failed tasks rate.
   - alert: HighVinylSchedulerFailedTasksRate
-    expr: rate(tnt_vinyl_scheduler_tasks{status="failed"}[2m]) > 0.1
+    expr: rate(tnt_vinyl_scheduler_tasks{status="failed"}[5m]) > 0.1
     for: 1m
     labels:
       severity: critical

example_cluster/prometheus/test_alerts.yml

@@ -333,9 +333,9 @@ tests:
   - interval: 15s
     input_series:
       - series: tnt_vinyl_scheduler_tasks{job="tarantool", instance="app:8081", alias="tnt_storage_master", status="failed"}
-        values: '2+3x10'
+        values: '2+3x40'
     alert_rule_test:
-      - eval_time: 2m
+      - eval_time: 5m
         alertname: HighVinylSchedulerFailedTasksRate
         exp_alerts:
           - exp_labels: