proxy: v2.166.0 (#7244)

This release updates the proxy's `rustls`, `ring`, and `webpki` dependencies.

Additionally, the proxy can now be built to use a `boringssl` backend
instead of the default `rustls` backend, but this functionality is
disabled in default builds.

---

* meshtls: replace build script with `compile_error!` macro (linkerd/linkerd2-proxy#1357)
* ci: Split actions into several workflows (linkerd/linkerd2-proxy#1356)
* ci: Make job names uniform (linkerd/linkerd2-proxy#1358)
* meshtls: allow building without any TLS impls enabled (linkerd/linkerd2-proxy#1359)
* `app-core` should not enable `meshtls-rustls` (linkerd/linkerd2-proxy#1360)
* Restore rustls credential tests (linkerd/linkerd2-proxy#1363)
* build(deps): bump hex from 0.3 to 0.4 (linkerd/linkerd2-proxy#1364)
* ci: Split jobs into 'fast' and 'slow' workflows (linkerd/linkerd2-proxy#1365)
* meshtls: Move TLS e2e tests into the meshtls crate (linkerd/linkerd2-proxy#1366)
* rustls: Tidy std::task imports (linkerd/linkerd2-proxy#1367)
* build(deps): bump serde_json from 1.0.68 to 1.0.69 (linkerd/linkerd2-proxy#1368)
* build(deps): bump libc from 0.2.106 to 0.2.107 (linkerd/linkerd2-proxy#1369)
* meshtls: Add a `boring` backend (linkerd/linkerd2-proxy#1351)
* meshtls-rustls: update to `rustls` 0.20 and `tokio-rustls` 0.23 (linkerd/linkerd2-proxy#1362)

.proxy-version

@@ -1 +1 @@
-v2.165.1
+v2.166.0