Update Readme to point to PSResourceGet documentation when it's released

[kilasuit]

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest released version
• Search the existing issues.

Steps to reproduce

The documentation button in the readme was updated to be labeled as PSResourceGet but the link points to the old PowerShellGet docs which was amended in #1296

Expected behavior

Link takes you to correct docs

Actual behavior

Takes you to old docs

Error details

No response

Environment data

not required

Visuals

No response