Fix BWC CI for 2.18 (opensearch-project#2124)

Signed-off-by: Naveen Tatikonda <[email protected]>

Author: naveentatikonda

.github/workflows/backwards_compatibility_tests_workflow.yml

@@ -35,7 +35,7 @@ jobs:
       matrix:
         java: [ 21 ]
         os: [ubuntu-latest]
-        bwc_version : [ "2.0.1", "2.1.0", "2.2.1", "2.3.0", "2.4.1", "2.5.0", "2.6.0", "2.7.0", "2.8.0", "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-SNAPSHOT"]
+        bwc_version : [ "2.0.1", "2.1.0", "2.2.1", "2.3.0", "2.4.1", "2.5.0", "2.6.0", "2.7.0", "2.8.0", "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-SNAPSHOT"]
         opensearch_version : [ "3.0.0-SNAPSHOT" ]
         exclude:
           - os: windows-latest
@@ -114,7 +114,7 @@ jobs:
       matrix:
         java: [ 21 ]
         os: [ubuntu-latest]
-        bwc_version: [ "2.17.0-SNAPSHOT" ]
+        bwc_version: [ "2.18.0-SNAPSHOT" ]
         opensearch_version: [ "3.0.0-SNAPSHOT" ]
 
     name: k-NN Rolling-Upgrade BWC Tests