Update helm and kubectl versions

[NiccoloFei]

The versions of helm and kubectl currently being installed are affected by CVE-2024-24790, which makes the marketplace's validation process fail with the following error:

  "taskReports": [
    {
      "taskType": "CHECK_PACKAGE_VULNERABILITIES",
      "createTime": "2024-06-25T11:07:08.452Z",
      "taskExecutionStatus": "ISSUES_FOUND",
      "digest": "Entity has one or more images with vulnerabilities.",
      "errorMessage": "Packages below are known to contain vulnerabilities. Please update the affected packages and resubmit the solution\n\nImage: https://gcr.io/cloud-launcher-images-prd/<redacted>\n  Note: CVE-2024-24790\n  Package: go\n  Package Type: GO_STDLIB\n  Affected Version: 1.20.11\n  Fixed Version: 1.21.11\n  Package: go\n  Package Type: GO_STDLIB\n  Affected Version: 1.21.6\n  Fixed Version: 1.21.11\n  Package: go\n  Package Type: GO_STDLIB\n  Affected Version: 1.21.7\n  Fixed Version: 1.21.11"
    },

[NiccoloFei]

Fixed in #630