Update dependencies to platform version 1.26.7

[danielpeach]

Event

{
  "branchName": "release-1.26.x",
  "createTag": true,
  "dependencyUpdates": [
    {
      "depName": "echo",
      "depVersion": "2.17.1-20210429125836"
    },
    {
      "depName": "kork",
      "depVersion": "7.109.0"
    }
  ],
  "hasDependencyUpdates": true,
  "newGradleProperties": "spinnakerRelease=1.26.7\norg.gradle.parallel=true\n\nspinnakerGradleVersion=8.6.0\npf4jVersion=3.2.0\nkorkVersion=7.109.0\nechoVersion=2.17.1-20210429125836\nkotlinVersion=1.3.72",
  "orgName": "spinnaker-plugin-examples",
  "platformVersion": "1.26.7",
  "repoId": "MDEwOlJlcG9zaXRvcnkyNzYzODM1MTE=",
  "repoName": "notificationPlugin"
}