Drop checkRequire for prefer-node-protocol

[voxpelli]

As a follow up to #1803, which dropped support for Node 12, I want to add this follow up to #1206 as it itself references Node 12 and dropping checkRequire when Node 12 is no longer needed to be supported:

We'll remove this option and check require(…) by default once this feature get backported to v12.

Though erroneously the docs also claim that the node:-protocol is only supported in require(...) for Node 16 and later. It actually is supported in Node ^14.18 || >=16 as @MylesBorins was tweeting and I digged into as a response on Twitter.

Suggestion

1. Make checkRequire a mandatory part of the rule and remove the option.
2. Update engines.node in package.json to be ^14.18 || >=16 to indicate this