Update package.json and package-lock.json so test script warns on broken links

[thebiggest0]

Package.json

• Change devDependencies for mark-down-link from “^3..10.3” (https://github.com/tcort/markdown-link-check) to https://github.com/thebiggest0/markdown-link-check.
• Reason: To prevent an error from being thrown when a broken link is encountered, the javascript in markdown-link-check needed to be changed. And for the change to be retained for future use this was the solution I found.

Package-lock.json

• Update content to reflect changes made to package.json (through npm install).
• Changes: mark-down-link resolved points to https://github.com/thebiggest0/markdown-link-check instead of the original registry on http://npmjs.org/.
• Changes: The version is now 3.10.4 (before 3.10.3) to reflect the changes I made in the markdown-link-check file. In the function runMarkdownLinkCheck() in the if condition which checks for broken links I changed console.error to console.warn and removed resolve(), now promise does not fail when encountering a broken link.