Update CHANGELOG.md for 12.6.1

[ci skip]

CHANGELOG.md

@@ -2,6 +2,18 @@
 documentation](doc/development/changelog.md) for instructions on adding your own
 entry.
 
+## 12.6.1
+
+### Fixed (2 changes)
+
+- Handle forbidden error when checking for knative. !22170
+- Fix stack trace highlight for PHP. !22258
+
+### Performance (1 change)
+
+- Eliminate N+1 queries in PipelinesController#index. !22189
+
+
 ## 12.6.0
 
 ### Security (4 changes)

changelogs/unreleased/121714-fix-sentry-stack-trace-highlight-for-php.yml

----
-title: Fix stack trace highlight for PHP
-merge_request: 22258
-author:
-type: fixed

changelogs/unreleased/alexives-119379-handle_http_error_instead_of_not_found.yml

----
-title: Handle forbidden error when checking for knative
-merge_request: 22170
-author:
-type: fixed

changelogs/unreleased/sh-optimize-pipeline-sql.yml

----
-title: Eliminate N+1 queries in PipelinesController#index
-merge_request: 22189
-author:
-type: performance