chore(deps): update docker.io/grafana/grafana-image-renderer docker tag to v5.8.1 (#1514)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

kubernetes/apps/monitoring/grafana/app/renderer.yaml

@@ -30,7 +30,7 @@ spec:
           main:
             image:
               repository: docker.io/grafana/grafana-image-renderer
-              tag: v5.8.0@sha256:0f61a5e8d0e22fbe96173701185e93235fef30567f3b35a80a0ceda82737c874
+              tag: v5.8.1@sha256:1f2b6832d06b4dda84267b712f51b91d20d7a3fdfca4239f042f86e100948a5c
     service:
       main:
         controller: main