Ignore 3.0 branch for breaking changes check (#18030) (#18033)

We'll need to come back and update this after the 3.0 release but for
now we should not be enforcing breaking changes against 3.0.


(cherry picked from commit 29585ef)

Signed-off-by: Andrew Ross <andrross@amazon.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: opensearch-trigger-bot[bot]

.github/workflows/detect-breaking-change.yml

@@ -3,6 +3,7 @@ on:
   pull_request:
     branches-ignore:
       - main # This branch represents a to-be-released version of OpenSearch where breaking changes are allowed
+      - '3.0' # We must establish a baseline 3.0 release version before adding enforcement
 
 jobs:
   detect-breaking-change:
@@ -26,4 +27,3 @@ jobs:
       with:
         name: java-compatibility-report.html
         path: ${{ github.workspace }}/server/build/reports/java-compatibility/report.html
-