[MCP] Bump rmcp to 0.8.2 (openai#5423)

[Release
notes](https://github.com/modelcontextprotocol/rust-sdk/releases)

Notably, this picks up two of my PRs that have four separate fixes for
oauth dynamic client registration and auth
modelcontextprotocol/rust-sdk#489
modelcontextprotocol/rust-sdk#476

Author: gpeal

codex-rs/Cargo.lock

@@ -153,7 +153,7 @@ ratatui = "0.29.0"
 ratatui-macros = "0.6.0"
 regex-lite = "0.1.7"
 reqwest = "0.12"
-rmcp = { version = "0.8.0", default-features = false }
+rmcp = { version = "0.8.2", default-features = false }
 schemars = "0.8.22"
 seccompiler = "0.5.0"
 sentry = "0.34.0"