Bump WordPress and PHP minimums

[vikrampm1]

Bump WP & PHP Minimums to the following

• [ ] WordPress to 5.7
• [ ] PHP to 7.4
• [ ] Remove any no-longer-needed conditional code for older version support.
• [ ] Take a look at adjusting our testing matrices, if applicable.
• [ ] Bump the minimums in plugin documentation and header fields.

[Sidsector9]

@vikrampm1 this repo isn't a WordPress plugin/extension that requires these changes. I am closing this.