Automated cherry pick of #1487: bump golang base image to 1.26.8 - #1493

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5, actions/dependency-review-action@2031cfc080254a8a887f58cffee85186f0e49e48. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/