[prometheus-blackbox-exporter] Update dependency prometheus/blackbox_exporter to v0.28.0 (#6385)

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

Author: renovate[bot]

charts/prometheus-blackbox-exporter/Chart.yaml

@@ -1,9 +1,9 @@
 apiVersion: v2
 description: Prometheus Blackbox Exporter
 name: prometheus-blackbox-exporter
-version: 11.5.0
+version: 11.6.0
 # renovate: github=prometheus/blackbox_exporter
-appVersion: v0.27.0
+appVersion: v0.28.0
 kubeVersion: ">=1.21.0-0"
 home: https://github.com/prometheus/blackbox_exporter
 sources: