refactor ilert readme

Signed-off-by: yacut <roman.rogozhnikov@gmail.com>

microsite/data/plugins/ilert.yaml

@@ -1,9 +1,9 @@
 ---
 title: iLert
 author: iLert
-authorUrl: https://github.com/iLert
+authorUrl: https://ilert.com
 category: Monitoring
-description: iLert is a platform for alerting, on-call management and uptime monitoring.
+description: iLert is a platform for alerting, on-call management and uptime monitoring targeted at DevOps and IT teams.
 documentation: https://github.com/backstage/backstage/tree/master/plugins/ilert
 iconUrl: https://avatars.githubusercontent.com/u/13230510?s=200&v=4
 npmPackageName: '@backstage/plugin-ilert'
@@ -11,3 +11,5 @@ tags:
   - monitoring
   - errors
   - alerting
+  - uptime
+  - on-call