build(release): enable R8 shrinking and obfuscation - #17

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: android-actions/setup-android@9fc6c4e9069bf8d3d10b2204b1fb8f6ef7065407. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/