Support for hCaptcha as a 'swap out' service

[hcuk94]

Since hCaptcha is increasingly popular, it would be great to support this as well as reCaptcha - the two services can be interchanged easily: https://docs.hcaptcha.com/switch/

I don't believe this would be a huge change, mainly just offering a different set of endpoint URLs.

If there's appetite for this package to expand to support hCaptcha, then I can have a look into the work needed and create a PR.

[pdupavillon]

Thanks for that suggestion,
There is already an existing lib (referenced on the page you mentioned): https://github.com/vastus/express-hcaptcha
I'll take a look at it and see if it's worth adding it.