chore(deps): update grafana-operator docker tag to v5.20.0 (#423)

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

Author: renovate[bot]

k8s/infra/monitoring/grafana/kustomization.yaml

@@ -16,6 +16,6 @@ helmCharts:
     repo: oci://ghcr.io/grafana/helm-charts
     includeCRDs: true
     namespace: grafana
-    version: v5.19.4 # renovate: github-releases=grafana/grafana-operator
+    version: v5.20.0 # renovate: github-releases=grafana/grafana-operator
     releaseName: grafana-operator
     valuesFile: ./values.yaml