LG-10628: Enable Dependabot updates for phone dependencies

[aduth]

🎫 Ticket

LG-10628

🛠 Summary of changes

Adds auto-updater configurations to the existing Dependabot configuration to automatically create pull requests for updates to dependencies which are used for phone metadata and validation:

• libphonenumber-js (npm)
• phonelib (ruby)

Why?

• Outdated phone metadata can prevent users from using certain phone numbers, as was the case with Update phonelib dependencies to add support for newer area codes #8932

Reference:

• https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file

📜 Testing Plan

This is difficult to test, since it would only be expected to take effect once the configuration changes are merged and a dependency update is available.

[aduth]

I think we're already behind on these dependencies, so I suspect we'll get one or more of these pull requests shortly after merging. Let's find out!