Feature: Expose deployment inspector url

[masonmcelvain]

Problem

When deploying to Vercel, it can be useful to inspect the deployment (especially if the deploy fails). The action does not expose the inspector url, so users of the action must use vercel inspect <preview-url> themselves to get the deployment url.

deploy-to-vercel-action exposes this feature.

https://github.com/BetaHuhn/deploy-to-vercel-action/blob/643bc80032ba62ca41d1a9aaba7b38b51c2b8646/src/vercel.js#L96-L107
https://github.com/BetaHuhn/deploy-to-vercel-action/blob/643bc80032ba62ca41d1a9aaba7b38b51c2b8646/src/index.js#L164-L167

Request

Please expose the inspector url as an additional action output.