Merge branch 'axil-fix-date-blueprint' into 'master'

Add creation-date of blueprint in quotes

Closes gitlab-docs#1339

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/106799



Merged-by: Grzegorz Bizon <grzegorz@gitlab.com>
Approved-by: Grzegorz Bizon <grzegorz@gitlab.com>
Co-authored-by: Achilleas Pipinellis <axil@gitlab.com>

doc/architecture/blueprints/gitlab_observability_backend/metrics/index.md

 ---
 status: proposed
-creation-date: 2022-11-09
+creation-date: "2022-11-09"
 authors: [ "@ankitbhatnagar" ]
 coach: "@mappelman"
 approvers: [ "@sebastienpahl", "@nicholasklick" ]