chore(deps): lock file maintenance rust crates (#49)

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This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
|  |  | lockFileMaintenance | All locks refreshed |
| [proc-macro2](https://togithub.com/dtolnay/proc-macro2) | dependencies
| patch | `1.0.83` -> `1.0.84` |
| [syn](https://togithub.com/dtolnay/syn) | dependencies | patch |
`2.0.65` -> `2.0.66` |

🔧 This Pull Request updates lock files to use the latest dependency
versions.

---

### Release Notes

<details>
<summary>dtolnay/proc-macro2 (proc-macro2)</summary>

###
[`v1.0.84`](https://togithub.com/dtolnay/proc-macro2/releases/tag/1.0.84)

[Compare
Source](https://togithub.com/dtolnay/proc-macro2/compare/1.0.83...1.0.84)

- Documentation improvements
([#&#8203;455](https://togithub.com/dtolnay/proc-macro2/issues/455),
thanks
[@&#8203;CensoredUsername](https://togithub.com/CensoredUsername))

</details>

<details>
<summary>dtolnay/syn (syn)</summary>

### [`v2.0.66`](https://togithub.com/dtolnay/syn/releases/tag/2.0.66)

[Compare
Source](https://togithub.com/dtolnay/syn/compare/2.0.65...2.0.66)

- Allow braced structs when parsing ExprLet
([#&#8203;1671](https://togithub.com/dtolnay/syn/issues/1671))

</details>

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