Build/Test Tools: Pin 22.3.0 version of Gutenberg for E2E tests in 6.8.

This pins the last version of the Gutenberg plugin compatible with the 6.8 branch (`22.3.0`) to the E2E test workflow.

Previously in other branches: [59518], [60214].

Fixes #64660.

git-svn-id: https://develop.svn.wordpress.org/branches/6.8@61665 602fd350-edb4-49c9-b593-d223f7449a82

Author: desrosj

.github/workflows/end-to-end-tests.yml

@@ -65,6 +65,7 @@ jobs:
         LOCAL_SCRIPT_DEBUG: [ true, false ]
     with:
       LOCAL_SCRIPT_DEBUG: ${{ matrix.LOCAL_SCRIPT_DEBUG }}
+      gutenberg-version: '22.3.0'
 
   slack-notifications:
     name: Slack Notifications