fix(rest-connector): add hint about breaking change in 8.6

[ztefanie]

Description

The behavior for grouping headers had a breaking change from 8.5 to 8.6. This is now documented.

When should this change go live?

• This is a bug fix, security concern, or something that needs urgent release support. (add bug or support label)
• This is already available but undocumented and should be released within a week. (add available & undocumented label)
• This is on a specific schedule and the assignee will coordinate a release with the DevEx team. (create draft PR and/or add hold label)
• This is part of a scheduled alpha or minor. (add alpha or minor label)
• There is no urgency with this change (add low prio label)

PR Checklist

• My changes are for an upcoming minor release and:
  • are in the /docs directory (version 8.8).
  • are in the /versioned_docs/version-8.7/ directory (version 8.7).
• My changes are for an already released minor and are in a /versioned_docs directory.

• I added a DRI, team, or delegate as a reviewer for technical accuracy and grammar/style:
  • Engineering team review
  • Technical writer review via @camunda/tech-writers unless working with an embedded writer.

[akeller]

@ztefanie, can you link to an issue or support ticket for reviewers to have a complete picture? Was this really a breaking change or a bug fix that was addressed in a patch?

[ztefanie]

@ztefanie, can you link to an issue or support ticket for reviewers to have a complete picture? Was this really a breaking change or a bug fix that was addressed in a patch?

Sure it is about this There is a discussion on going in the incident slack channel: #inc-support-26056-multiple-set-cookie-headers

[johnBgood]

Thank you!

[christinaausley]

This breaking change should also likely go into announcements.

[github-actions]

👋 🤖 🤔 Hello, @ztefanie! Did you make your changes in all the right places?

These files were changed only in versioned_docs/version-8.6/. You might want to duplicate these changes in docs/.

• versioned_docs/version-8.6/reference/announcements.md

These files were changed only in versioned_docs/version-8.6/. You might want to duplicate these changes in versioned_docs/version-8.7/.

• versioned_docs/version-8.6/reference/announcements.md

You may have done this intentionally, but we wanted to point it out in case you didn't. You can read more about the versioning within our docs in our documentation guidelines.

[ztefanie]

See related issue

I did not document the "breaking change" in the last two lines of the table below, because i consider this a bug fix and not a breaking change.

Behavior	Expected result
Users are on 8.5 and update to 8.6.11	nothing should break
Users are on 8.5 and update to 8.6.7	will break but should be fixed with manually editing the template
Users are on 8.6.7 and did edit their template and update to 8.6.11	should work fine
Users are on 8.6.7 and did not edit their template and update to 8.6.11	breaking change: if using a set cookie header in a feel result, this will fail, as now an array is returned
Users are on 8.6.7 or higher and update to 8.7	breaking change: if using a set cookie header in a feel result, this will fail, as now an array is returned

[github-actions]

The preview environment relating to the commit bb60a8c has successfully been deployed. You can access it at https://preview.docs.camunda.cloud/pr-5137/index.html

[neal-dennis]

LGTM