upgrade to beta1 from alpha1 for 3.0 release (#733)

Signed-off-by: will-hwang <[email protected]>

Author: will-hwang

build.gradle

@@ -48,8 +48,8 @@ validateNebulaPom.enabled = false
 
 buildscript {
     ext {
-        opensearch_version = System.getProperty("opensearch.version", "3.0.0-alpha1-SNAPSHOT")
-        buildVersionQualifier = System.getProperty("build.version_qualifier", "alpha1")
+        opensearch_version = System.getProperty("opensearch.version", "3.0.0-beta1-SNAPSHOT")
+        buildVersionQualifier = System.getProperty("build.version_qualifier", "beta1")
         isSnapshot = "true" == System.getProperty("build.snapshot", "true")
         // 2.2.0-SNAPSHOT -> 2.2.0.0-SNAPSHOT
         version_tokens = opensearch_version.tokenize('-')