patch(prometheus): bump to 3.15.0 - #85

buildx failed with: ERROR: failed to build: failed to solve: process "/bin/sh -c apt-get update && apt-get install -y sudo && rm -rf /var/lib/apt/lists/*" did not complete successfully: exit code: 100

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, docker/build-push-action@v5, docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/