Increment version to 3.4.0-SNAPSHOT (#137)

Signed-off-by: opensearch-ci-bot <[email protected]>
Co-authored-by: opensearch-ci-bot <[email protected]>

Author: opensearch-trigger-bot[bot]

build.gradle

@@ -35,7 +35,7 @@ forbiddenApisTest.enabled = false
 
 buildscript {
     ext {
-        opensearch_version = System.getProperty("opensearch.version", "3.3.0-SNAPSHOT")
+        opensearch_version = System.getProperty("opensearch.version", "3.4.0-SNAPSHOT")
         buildVersionQualifier = System.getProperty("build.version_qualifier", "")
         isSnapshot = "true" == System.getProperty("build.snapshot", "true")
         version_tokens = opensearch_version.tokenize('-')