CI: BWC testsuite (#3255)

* Bump base version to 2.19.0

Signed-off-by: Andy Kwok <[email protected]>

* Update comment

Signed-off-by: Andy Kwok <[email protected]>

---------

Signed-off-by: Andy Kwok <[email protected]>

Author: andy-k-improving

integ-test/build.gradle

@@ -44,7 +44,10 @@ apply plugin: 'java'
 apply plugin: 'io.freefair.lombok'
 apply plugin: 'com.wiredforcode.spawn'
 
-String baseVersion = "2.17.0"
+// The next major version is only API compat w/ the last minor of the previous major.
+// baseVersion need to roll-froward accordingly, as new 2.x of OpenSearch being released.
+// See: https://github.com/opensearch-project/OpenSearch/issues/3615
+String baseVersion = "2.19.0"
 String bwcVersion = baseVersion + ".0";
 String baseName = "sqlBwcCluster"
 String bwcFilePath = "src/test/resources/bwc/"