feat: add serde feature for web_time::SystemTime (#17)

## Description

Makes the `SystemTime` version for Wasm compatible with serde.

## Breaking Changes

<!-- Optional, if there are any breaking changes document them,
including how to migrate older code. -->

## Notes & open questions

<!-- Any notes, remarks or open questions you have to make about the PR.
-->

## Change checklist

- [ ] Self-review.
- [ ] Documentation updates following the [style
guide](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#appendix-a-full-conventions-text),
if relevant.
- [ ] Tests if relevant.
- [ ] All breaking changes documented.

Author: Frando

Cargo.lock

@@ -62,3 +62,6 @@ unexpected_cfgs = { level = "warn", check-cfg = ["cfg(n0_future_docsrs)"] }
 
 [lints.clippy]
 unused-async = "warn"
+
+[features]
+serde = ["web-time/serde"]

Cargo.toml

@@ -29,6 +29,10 @@ We do this in a couple of ways:
 
 It's entirely possible that we'll expand the scope of this library, that currently is mostly a re-exports crate to a crate that provides our own flavor of async APIs that we deem are safer to use, we write about some of these ideas in this issue: https://github.com/n0-computer/iroh/issues/2979
 
+## Feature flags
+
+* `serde`: Enables serde support for the [`time::SystemTime`] type when building for WebAssembly.
+
 ## Note to Maintainers: Creating a release
 
 - Make sure to have `git-cliff`, `cargo-release` and `cargo-semver-checks` installed.

README.md

@@ -5,6 +5,10 @@
 //! This library also allows importing a single [`task`] and [`time`] module that'll work
 //! in `wasm*-*-unknown` targets, using `wasm_bindgen` and `wasm_bindgen_futures`, but mirroring
 //! the `tokio` API with only minor differences.
+//!
+//! ## Feature flags
+//!
+//! * `serde`: Enables serde support for the [`time::SystemTime`] type when building for WebAssembly.
 
 #![deny(missing_docs, rustdoc::broken_intra_doc_links)]
 #![cfg_attr(not(test), deny(clippy::unwrap_used))]