docs: record published v2.2.0 and close KN-5 tracker - #23

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@11d5960a326750d5838078e36cf38b85af677262, actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065, bufbuild/buf-setup-action@a47c93e0b1648d5651a065437926377d060baa99. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/