Reasons for making this change

I wanted to use "npx gitignore" with my new Astro project. I then found out that there is no gitignore for Astro in this repo.

Links to documentation supporting these rule changes

I couldn't find any documentation showing the gitignore file. I used the gitignore file from the astro repo from withastro.

https://github.com/withastro/astro/blob/main/.gitignore
https://github.com/withastro/astro/

If this is a new template

Link to application or project’s homepage: https://astro.build/

Merge and Approval Steps

• Confirm that you've read the contribution guidelines and ensured your PR aligns
• Ensure CI is passing
• Get a review and Approval from one of the maintainers