Add servicesJsonRoute option and remove unneeded dependency

[Vincentdevreede]

• Feature: Introduced the servicesJsonRoute option to control the exposure of service documentation.
• Chore: Removed unneeded @polka/send-type dependency

💻 Code example:

const server = gateway({
  servicesJsonRoute: false, // optional, default value: true
  routes: [
    {
      prefix: '/service',
      target: 'http://127.0.0.1:3000',
    },
  ],
})

ℹ️ Note:
I used version number 4.2.0 in the documentation, assuming that will be the next release version. Please let me know if a different version is used.

[Copilot]

Pull Request Overview

This PR introduces a new option to control the exposure of service documentation via a JSON route and removes an unneeded dependency.

• Added a new servicesJsonRoute option with a default value of true in gateway configuration.
• Replaced the usage of @polka/send-type with a built‐in response method for serving /services.json.
• Updated documentation to reflect the new option and version changes.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
package.json	Removed the unneeded @polka/send-type dependency.
index.js	Added servicesJsonRoute option and updated the JSON route handler.
docs/README.md	Updated documentation to include the new servicesJsonRoute option.