Update to ratatui 0.26

[holly-hacker]

Hi, tui-textarea currently targets ratatui 0.24.0, but the latest version is 0.26.1. Could you update the dependency and publish a new release?

[joshka]

Tui-textarea's >=0.23 version spec means you only have to run cargo update and you'll be using the latest version released. (0.26.2 at time of writing). This is actually bad behavior as it causes the problems mentioned in:

• https://doc.rust-lang.org/cargo/reference/resolver.html#unexpected-dependency-duplication
• https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#multiple-version-requirements

[rhysd]

This issue was solved by #69.