chore(deps): Update Rust crate snapbox to v0.6.20 (#41)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
|
[snapbox](https://redirect.github.com/assert-rs/trycmd/tree/main/crates/snapbox)
([source](https://redirect.github.com/assert-rs/snapbox)) |
dev-dependencies | patch | `0.6.19` -> `0.6.20` |

---

### Release Notes

<details>
<summary>assert-rs/snapbox (snapbox)</summary>

###
[`v0.6.20`](https://redirect.github.com/assert-rs/snapbox/compare/snapbox-v0.6.19...snapbox-v0.6.20)

[Compare
Source](https://redirect.github.com/assert-rs/snapbox/compare/snapbox-v0.6.19...snapbox-v0.6.20)

</details>

---

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