added missing query parameter for HEAD /sources

[danjhd]

Details

Added missing format query parameter to the HEAD /sources endpoint to ensure consistency with the GET /sources endpoint

Jira Issue (if relevant)

Jira URL: n/a

Related PRs

Where appropriate. Indicate order to be merged.

Submitter PR Checks

(tick as appropriate)

• PR completes task/fixes bug
• API version has been incremented if necessary
• ADR status has been updated, and ADR implementation has been recorded
• Documentation updated (README, etc.)
• PR added to Jira Issue (if relevant)
• Follow-up stories added to Jira

Reviewer PR Checks

(tick as appropriate)

• PR completes task/fixes bug
• Design makes sense, and fits with our current code base
• Code is easy to follow
• PR size is sensible
• Commit history is sensible and tidy

Info on PRs

The checks above are guidelines. They don't all have to be ticked, but they should all have been considered.

[philipnbbc]

LGTM