Update security-policy.mdx

[ryenmac-nr]

Please follow conventional commit standards
in your commit messages and pull request title.

Give us some context

• What problems does this PR solve?
  docs: Changed Updated 23 September 2021 to reflect 26 Oct commit on section 4.2
• Add any context that will help us review your changes such as testing notes,
  links to related docs, screenshots, etc.
  db90873
• If your issue relates to an existing GitHub issue, please link to it.

[CLAassistant]

All committers have signed the CLA.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[github-actions]

Hi @ryenmac-nr 👋

Thanks for your pull request! Your PR is in a queue, and a writer will take a look soon. We generally publish small edits within one business day, and larger edits within three days.

Gatsby Cloud will automatically generate a preview of your request, and will comment with a link when the preview is ready (usually 20 to 30 minutes).

[ghost]

✅ docs-website-develop deploy preview ready

• Deploy preview
• Build logs · 50m build time

[rhetoric101]

@ryenmac-nr thanks for updating this date!