Strictly check for Node 16 LTS and lockfile v3

[ferferga]

• Enforces the engine checks to enforce the current LTS version (16 at the time of writing). The minimum version check of 16.3.1 and npm 8.1.2 is to ensure that users has an npm version that doesn't have problems when installing dependencies using the v3 lockfile (see fix: allow --lockfile-version config to be string and coerce to number npm/cli#3949). Node 16.3.1 was the earliest node version to include the npm update with the fix.
• Upgrades to the v3 lockfile format.