⬆️ Update rstest requirement from 0.17 to 0.18#17

dependabot[bot] wants to merge 1 commit intomainmarkdown-it-rust/markdown-it-plugins.rs:mainfrom

dependabot/cargo/rstest-0.18markdown-it-rust/markdown-it-plugins.rs:dependabot/cargo/rstest-0.18Copy head branch name to clipboard