fix: update certgen image to fix cves

[ed382]

Pull request description

kubeshop/kube-webhook-certgen: docker scout cves kubeshop/kube-webhook-certgen:0.0.7                                                                                                                            
    i New version 1.16.1 available (installed version is 1.15.1) at https://github.com/docker/scout-cli
    ✓ Pulled
    ✓ Image stored for indexing
    ✓ Indexed 49 packages
    ✓ No vulnerable package detected


## Overview

                    │            Analyzed Image
────────────────────┼────────────────────────────────────────
  Target            │  kubeshop/kube-webhook-certgen:0.0.7
    digest          │  bf6d7698fbb7
    platform        │ linux/arm64
    vulnerabilities │    0C     0H     0M     0L
    size            │ 12 MB
    packages        │ 49


## Packages and Vulnerabilities

  No vulnerable packages detected

Checklist (choose whats happened)

• breaking change! (describe)
• tested locally
• tested on cluster
• added new dependencies
• updated the docs
• added a test

Breaking changes

Changes

Fixes