Update to 26.3 - #686

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29, actions/setup-java@99b8673ff64fbf99d8d325f52d9a5bdedb8483e9, gradle/actions/setup-gradle@db19848a5fa7950289d3668fb053140cf3028d43, gradle/actions/wrapper-validation@db19848a5fa7950289d3668fb053140cf3028d43. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/