docs: some contents are missing

[jsparkdev]

1. The CONTRIBUTING.md file does not exist in the .github folder, causing a 404 error when clicking CONTRIBUTING in the README.
2. The /usage/query-param/query-param-required.gif file in the document doesn't exist, so an alternate image is displayed.

[kss2002]

@leegeunhyeok
@jsparkdev

Hello! I don't think part 1 of the issue posted by jsparkdev has been solved yet!
Please check!