[9.0](backport #5580) Update CODEOWNERS (#5586)

Author: mergify[bot]

.github/CODEOWNERS

@@ -3,3 +3,7 @@
 
 # Allow to auto-merge PRs with Mergify
 dev-tools/integration/.env
+/.github/workflows @elastic/observablt-ci
+/.github/workflows/golangci-lint.yml @elastic/elastic-agent-control-plane
+/docs/release-notes @elastic/ingest-docs
+/docs/docset.yml @elastic/ingest-docs