build(deps): bump uart_16550 from 0.2.18 to 0.2.19

Bumps [uart_16550](https://github.com/rust-osdev/uart_16550) from 0.2.18 to 0.2.19.
- [Changelog](https://github.com/rust-osdev/uart_16550/blob/master/Changelog.md)
- [Commits](rust-osdev/uart_16550@v0.2.18...v0.2.19)

---
updated-dependencies:
- dependency-name: uart_16550
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>