Added cluster_id to DatabricksConfig for DBConnect (#102)

## Changes
<!-- Summary of your changes that are easy to understand -->
Python SDK for reference:
https://github.com/databricks/databricks-sdk-py/blob/main/databricks/sdk/core.py#LL392C2-L392C2.

## Tests
<!-- How is this tested? -->
PR Tests

Author: tanmay-db

databricks-sdk-java/src/main/java/com/databricks/sdk/core/DatabricksConfig.java

@@ -58,6 +58,9 @@ public class DatabricksConfig {
   @ConfigAttribute(value = "config_file", env = "DATABRICKS_CONFIG_FILE")
   private String configFile;
 
+  @ConfigAttribute(value = "cluster_id", env = "DATABRICKS_CLUSTER_ID")
+  private String clusterId;
+
   @ConfigAttribute(
       value = "google_service_account",
       env = "DATABRICKS_GOOGLE_SERVICE_ACCOUNT",
@@ -252,6 +255,15 @@ public DatabricksConfig setUsername(String username) {
     return this;
   }
 
+  public String getClusterId() {
+    return clusterId;
+  }
+
+  public DatabricksConfig setClusterId(String clusterId) {
+    this.clusterId = clusterId;
+    return this;
+  }
+
   public String getPassword() {
     return password;
   }