docs(gitlab bot security): rewrite

[HonkingGoose]

Changes

• Use admonition styling for important security message
• Rewrite most of the text
  • Use lists where needed
  • Use You to put the reader into the text
  • Use simpler words and phrases
  • Explain who does what by using We
  • Rewrite double negatives into a positive form
  • Abbreviate the term Personal Access Tokens

Context

A maintainer should check if this document is still relevant, or needs to be updated. I don't know if GitLab is safe to use with Renovate now, or if we're still waiting on things.

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository

[renovate-release]

🎉 This PR is included in version 37.92.1 🎉

The release is available on:

• GitHub release
• 37.92.1

Your semantic-release bot 📦🚀