chore: Dependency update and maintenance (#376)

* chore: Update dependencies to latest versions

- package.json - Upgrade @11ty/eleventy to 3.1.5
- package.json - Upgrade @11ty/eleventy-plugin-rss to 3.0.0
- package.json - Upgrade @11ty/eleventy-fetch to 5.1.2
- package.json - Upgrade markdown-it-table-of-contents to 1.2.0
- package.json - Upgrade sass to 1.98.0
- Keep dependencies up to date for security and compatibility

* chore: Update vulnerable packages

Author: VaclavElias