chore(rds): add Aurora PostgreSQL cluster engine version 14.12, 13.15…

… and 12.19 (#31094)

Add the cluster engines that were added in the following update.

[Amazon Aurora supports PostgreSQL 16.3, 15.7, 14.12, 13.15, and 12.19
](https://aws.amazon.com/about-aws/whats-new/2024/08/amazon-aurora-postgresql-new-version-support/)

* 16.3 was added in #31003
* 15.7 was added in #31085 


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

packages/aws-cdk-lib/aws-rds/lib/cluster-engine.ts

@@ -946,6 +946,8 @@ export class AuroraPostgresEngineVersion {
  public static readonly VER_12_17 = AuroraPostgresEngineVersion.of('12.17', '12', { s3Import: true, s3Export: true });
  /** Version "12.18". */
  public static readonly VER_12_18 = AuroraPostgresEngineVersion.of('12.18', '12', { s3Import: true, s3Export: true });
+ /** Version "12.19". */
+ public static readonly VER_12_19 = AuroraPostgresEngineVersion.of('12.19', '12', { s3Import: true, s3Export: true });
  /**
  * Version "13.3".
  * @deprecated Version 13.3 is no longer supported by Amazon RDS.
@@ -982,6 +984,8 @@ export class AuroraPostgresEngineVersion {
  public static readonly VER_13_13 = AuroraPostgresEngineVersion.of('13.13', '13', { s3Import: true, s3Export: true });
  /** Version "13.14". */
  public static readonly VER_13_14 = AuroraPostgresEngineVersion.of('13.14', '13', { s3Import: true, s3Export: true });
+ /** Version "13.15". */
+ public static readonly VER_13_15 = AuroraPostgresEngineVersion.of('13.15', '13', { s3Import: true, s3Export: true });
  /** Version "14.3". */
  public static readonly VER_14_3 = AuroraPostgresEngineVersion.of('14.3', '14', { s3Import: true, s3Export: true });
  /** Version "14.4". */
@@ -1000,6 +1004,8 @@ export class AuroraPostgresEngineVersion {
  public static readonly VER_14_10 = AuroraPostgresEngineVersion.of('14.10', '14', { s3Import: true, s3Export: true });
  /** Version "14.11". */
  public static readonly VER_14_11 = AuroraPostgresEngineVersion.of('14.11', '14', { s3Import: true, s3Export: true });
+ /** Version "14.12". */
+ public static readonly VER_14_12 = AuroraPostgresEngineVersion.of('14.12', '14', { s3Import: true, s3Export: true });
  /** Version "15.2". */
  public static readonly VER_15_2 = AuroraPostgresEngineVersion.of('15.2', '15', { s3Import: true, s3Export: true });
  /** Version "15.3". */