Update kubectl to v1.28.3, nginx to 1.25.3

This MR contains the following updates:

Package	Update	Change
registry1.dso.mil/ironbank/opensource/kubernetes/kubectl	patch	v1.28.2 -> v1.28.3
registry1.dso.mil/ironbank/opensource/nginx/nginx	patch	1.25.2 -> 1.25.3

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This MR has been generated by Renovate Bot.

chart/Chart.yaml

@@ -31,7 +31,7 @@ annotations:
     - name: loki
       image: registry1.dso.mil/ironbank/opensource/grafana/loki:2.9.2
     - name: kubectl
-      image: registry1.dso.mil/ironbank/opensource/kubernetes/kubectl:v1.28.2
+      image: registry1.dso.mil/ironbank/opensource/kubernetes/kubectl:v1.28.3
     - name: grafana-enterprise-logs
       image: registry1.dso.mil/ironbank/grafana/grafana-enterprise-logs:v1.7.1
       condition: enterprise.enabled
@@ -45,7 +45,7 @@ annotations:
       image: docker.io/grafana/loki-canary:2.9.2
       condition: monitoring.lokiCanary.enabled
     - name: nginx-gateway
-      image: registry1.dso.mil/ironbank/opensource/nginx/nginx:1.25.2
+      image: registry1.dso.mil/ironbank/opensource/nginx/nginx:1.25.3
       condition: gateway.enabled
     - name: minio
       image: registry1.dso.mil/ironbank/opensource/minio/minio:RELEASE.2023-06-19T19-52-50Z