should throw for non-string route URL

[Eomm]

Prerequisites

• I have written a descriptive issue title
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Issue

This snippet starts correctly:

const fastify = require('fastify')({ logger: true })

const handler = async (request, reply) => {
  return { hello: request.params.foo }
}

fastify.get(/^\/(donations|skills|blogs)/, handler)
fastify.listen(8080)

There is one error: the regExp on the route's URL.
In this case, I think we should throw an error.

Note that find-my-way is receiving a string because we are composing its route input checking the prefix etc..

Do you agree?

[mcollina]

Definitely!

[jsumners]

I think it's a semver-patch. It currently does not work, but does so without any warning.