Add .mil domain in supported Databricks environment (#435)

## What changes are proposed in this pull request?

Adding support for .mil domain as part of GOV domain support

## How is this tested?

Did a manual testing with a DoD domain using OSS Jdbc driver.

---------

Co-authored-by: Miles Yucht <[email protected]>

Author: gopalldb

NEXT_CHANGELOG.md

@@ -9,5 +9,6 @@
 ### Documentation
 
 ### Internal Changes
+* Added support for .cloud.databricks.mil domains ([#435](https://github.com/databricks/databricks-sdk-java/pull/435)).
 
 ### API Changes

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

@@ -50,6 +50,7 @@ public String getDeploymentUrl(String name) {
           new DatabricksEnvironment(Cloud.AWS, ".dev.databricks.com"),
           new DatabricksEnvironment(Cloud.AWS, ".staging.cloud.databricks.com"),
           new DatabricksEnvironment(Cloud.AWS, ".cloud.databricks.us"),
+          new DatabricksEnvironment(Cloud.AWS, ".cloud.databricks.mil"),
           DEFAULT_ENVIRONMENT,
           new DatabricksEnvironment(
               Cloud.AZURE,