feat(neptune): auto minor version upgrade for an instance (#31988)

### Issue # (if applicable)

None

### Reason for this change

Cloudformation supports for configuring `autoMinorVersionUpgrade` for a database instance but AWS CDK cannot do that.

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-neptune-dbinstance.html#cfn-neptune-dbinstance-autominorversionupgrade

### Description of changes

Add `autoMinorVersionUpgrade` to `DatabaseInstanceProps`

### Description of how you validated changes

Added both unit and integ tests.

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: badmintoncryer

packages/@aws-cdk/aws-neptune-alpha/README.md

@@ -138,6 +138,17 @@ new neptune.DatabaseCluster(this, 'Cluster', {
 });
 ```
 
+You can also specify `autoMinorVersionUpgrade` to a database instance.
+Even within the same cluster, you can modify the `autoMinorVersionUpgrade` setting on a per-instance basis.
+
+```ts fixture=with-cluster
+new neptune.DatabaseInstance(this, 'Instance', {
+  cluster,
+  instanceType: neptune.InstanceType.R5_LARGE,
+  autoMinorVersionUpgrade: true,
+});
+```
+
 ## Port
 
 By default, Neptune uses port `8182`. You can override the default port by specifying the `port` property:

packages/@aws-cdk/aws-neptune-alpha/awslint.json

@@ -3,6 +3,7 @@
     "props-physical-name:@aws-cdk/aws-neptune-alpha.ClusterParameterGroupProps",
     "props-physical-name:@aws-cdk/aws-neptune-alpha.ParameterGroupProps",
     "props-physical-name:@aws-cdk/aws-neptune-alpha.SubnetGroupProps",
-    "docs-public-apis:@aws-cdk/aws-neptune-alpha.ServerlessScalingConfiguration"
+    "docs-public-apis:@aws-cdk/aws-neptune-alpha.ServerlessScalingConfiguration",
+    "props-no-undefined-default:@aws-cdk/aws-neptune-alpha.DatabaseInstanceProps.autoMinorVersionUpgrade"
   ]
 }

packages/@aws-cdk/aws-neptune-alpha/lib/instance.ts

@@ -403,6 +403,13 @@ export interface DatabaseInstanceProps {
    * @default RemovalPolicy.Retain
    */
   readonly removalPolicy?: cdk.RemovalPolicy;
+
+  /**
+   * Indicates that minor version patches are applied automatically.
+   *
+   * @default undefined
+   */
+  readonly autoMinorVersionUpgrade?: boolean;
 }
 
 /**
@@ -494,6 +501,7 @@ export class DatabaseInstance extends DatabaseInstanceBase implements IDatabaseI
     super(scope, id);
 
     const instance = new CfnDBInstance(this, 'Resource', {
+      autoMinorVersionUpgrade: props.autoMinorVersionUpgrade,
       dbClusterIdentifier: props.cluster.clusterIdentifier,
       dbInstanceClass: props.instanceType._instanceType,
       availabilityZone: props.availabilityZone,

packages/@aws-cdk/aws-neptune-alpha/test/instance.test.ts

@@ -108,6 +108,23 @@ describe('DatabaseInstance', () => {
     });
   });
 
+  test.each([true, false])('instance with auto minor version upgrade', (autoMinorVersionUpgrade) => {
+    // GIVEN
+    const stack = testStack();
+
+    // WHEN
+    new DatabaseInstance(stack, 'Instance', {
+      cluster: stack.cluster,
+      instanceType: InstanceType.R5_LARGE,
+      autoMinorVersionUpgrade,
+    });
+
+    // THEN
+    Template.fromStack(stack).hasResourceProperties('AWS::Neptune::DBInstance', {
+      AutoMinorVersionUpgrade: autoMinorVersionUpgrade,
+    });
+  });
+
   test('instance type from CfnParameter', () => {
     // GIVEN
     const stack = testStack();