java-api should be compatible with all major core versions

Author: pesse

src/main/java/org/utplsql/api/compatibility/CompatibilityProxy.java

@@ -24,7 +24,7 @@
 public class CompatibilityProxy {
 
     public static final String UTPLSQL_API_VERSION = "3.1.0";
-    public static final String UTPLSQL_COMPATIBILITY_VERSION = "3.0";
+    public static final String UTPLSQL_COMPATIBILITY_VERSION = "3";
 
     private Version databaseVersion;
     private boolean compatible = false;