docs: move wasi-keyvalue proposal to tier 3 (bytecodealliance#9050)

Author: iawia002

docs/stability-tiers.md

@@ -97,12 +97,14 @@ For explanations of what each tier means see below.
 | WASI Proposal        | [`wasi-nn`]                       | More expansive CI testing   |
 | WASI Proposal        | [`wasi-threads`]                  | More CI, unstable proposal  |
 | WASI Proposal        | [`wasi-runtime-config`]           | unstable proposal           |
+| WASI Proposal        | [`wasi-keyvalue`]                 | unstable proposal           |
 | *misc*               | Non-Wasmtime Cranelift usage [^1] | CI testing, full-time maintainer |
 | *misc*               | DWARF debugging [^2]              | CI testing, full-time maintainer, improved quality |
 
 [`wasi-nn`]: https://github.com/WebAssembly/wasi-nn
 [`wasi-threads`]: https://github.com/WebAssembly/wasi-threads
 [`wasi-runtime-config`]: https://github.com/WebAssembly/wasi-runtime-config
+[`wasi-keyvalue`]: https://github.com/WebAssembly/wasi-keyvalue
 [`gc`]: https://github.com/WebAssembly/gc
 
 [^1]: This is intended to encompass features that Cranelift supports as a
@@ -157,7 +159,6 @@ features to figure out how best to implement them and at least move them to Tier
 * [WASI proposal: `wasi-data`](https://github.com/WebAssembly/wasi-data)
 * [WASI proposal: `wasi-distributed-lock-service`](https://github.com/WebAssembly/wasi-distributed-lock-service)
 * [WASI proposal: `wasi-grpc`](https://github.com/WebAssembly/wasi-grpc)
-* [WASI proposal: `wasi-kv-store`](https://github.com/WebAssembly/wasi-kv-store)
 * [WASI proposal: `wasi-message-queue`](https://github.com/WebAssembly/wasi-message-queue)
 * [WASI proposal: `wasi-parallel`](https://github.com/WebAssembly/wasi-parallel)
 * [WASI proposal: `wasi-pubsub`](https://github.com/WebAssembly/wasi-pubsub)