Docs will not build correctly for CMS 5 docs with 5.0 branch

[GuySartorelli]

For some reason, when changing the branch that docs looks at from 5 to 5.0 the preview shows that all routes for v5 docs are broken.

See the PR https://github.com/silverstripe/doc.silverstripe.org/pull/256 and its preview https://deploy-preview-256--ss-docs.netlify.app/

Acceptance criteria

• [x] Targetting at the 5.0 branch correctly fetched docs from that branch

PRs

• https://github.com/silverstripe/doc.silverstripe.org/pull/255

[emteknetnz]

Linked PR has been merged