Prevent execution if dependent plugins don't meet criteria

[jasonbahl]

It would be good to let users know if/when dependent plugins aren't compatible with this plugin.

For example, if this plugin required xx version (or newer) of WPGraphQL and xx version (or newer) of WPGraphQL Smart Cache, we should run this check and if criteria isn't met, bail early and show and admin notice.

Example code like this is in WPGraphQL for ACF: https://github.com/wp-graphql/wp-graphql-acf/blob/develop/wp-graphql-acf.php#L31-L47

^ may or may not be "ideal" code to follow, but a good start