Add src and more files to npmignore

Hi, I'm new to this lib community, and I just wanted to suggest adding more files to npmignore.

I don't know if it was intentional because I don't actively follow the development of this project, but I noticed that there were some files that I don't think are necessary in npm, such as:

• src
• .huskyrc
• CONTRIBUTING.md
• .lintstagedrc

Mainly src increases the size of the library.

If it was intentional, you can resolve this issue, thanks.