Bump some dependencies' versions; update code

- `cargo audit`
- `cargo update`
- Update code
- `cargo fmt`

```
$ cargo audit
...
Crate:     crossbeam-channel
Version:   0.5.13
Title:     crossbeam-channel: double free on Drop
Date:      2025-04-08
ID:        RUSTSEC-2025-0024
URL:       https://rustsec.org/advisories/RUSTSEC-2025-0024
Solution:  Upgrade to >=0.5.15
Dependency tree:
crossbeam-channel 0.5.13
└── oxipng 9.1.1
    └── reduce_image_size 0.2.3
```

Author: ivanbgd