Change the default config.kasAddress to grpcs://kas.gitlab.com

Changes the chart default config.kasAddress from wss://kas.gitlab.com to grpcs://kas.gitlab.com and regenerates the README with helm-docs -s file. The value's comment now says which scheme to use for native gRPC and for WebSocket.

kas.gitlab.com has accepted native gRPC since 2026-08-31 and GitLab.com is moving the advertised KAS address to grpcs://. Impact: releases that rely on the default connect over native gRPC on their next helm upgrade; releases that set config.kasAddress explicitly, including every install created from the GitLab UI command or glab cluster agent bootstrap, are unaffected. wss://kas.gitlab.com remains supported. The wss://kas.gitlab.example.com example in the README is a self-managed example and is intentionally left as is.

This is a behaviour change for anyone on the default, so the chart version is bumped to 2.31.0 here and a matching entry is added to the changelog in templates/NOTES.txt, which Helm prints after install and upgrade.

Context:

• Update defaults and docs for Relay grpcs (gitlab-org/gitlab#628011 - closed)
• Promote gRPC connections to GitLab Relay(KAS) o... (gitlab-org&23445 - closed)