Add bwc test from all old versions

Signed-off-by: Heemin Kim <heemin@amazon.com>

Author: heemin32

.github/workflows/backwards_compatibility_tests_workflow.yml

@@ -42,7 +42,7 @@ jobs:
       matrix:
         java: [ 21 ]
         os: [ubuntu-latest,windows-latest]
-        bwc_version: [ "2.19.0-SNAPSHOT" ]
+        bwc_version: ["2.9.0","2.10.0","2.11.0","2.12.0","2.13.0","2.14.0","2.15.0","2.16.0","2.17.0","2.18.0","2.19.0-SNAPSHOT"]
         opensearch_version: [ "3.0.0-SNAPSHOT" ]
 
     name: NeuralSearch Rolling-Upgrade BWC Tests