(doc) Add info about new Authenticode signature

[gep13]

Description Of Changes

Add a new section about the updated Authenticate signature that is applied to all official Chocolatey releases.

Motivation and Context

A new certificate has been purchased, since the previous one expired, and we needed to update this section with the correct information.

Testing

• [x] I have previewed these changes using the Docker Container or another method before submitting this pull request.

Change Types Made

• [ ] Minor documentation fix (typos etc.).
• [x] Major documentation change (refactoring, reformatting or adding documentation to existing page).
• [ ] New documentation page added.
• [ ] The change I have made should have a video added, and I have raised an issue for this.
  • Issue #

Change Checklist

• [ ] Requires a change to menu structure (top or left-hand side)/
• [ ] Menu structure has been updated

Related Issue

N/A

[gep13]

@AdmiringWorm this is marked as draft, as it won't be merged until the 2.3.0 release happens, but it is ready for a review. Thanks

[gep13]

@AdmiringWorm thank you for the review, I will merge once the CI build completes.