chore(rds): add support for Postgres versions 13.19, 13.20, 14.16, 14…

….17, 15.11, 15.12, 16.8, 17.3, and 17.4 (#33559)

Add minor versions.

* [Amazon RDS for PostgreSQL supports minor versions 17.4, 16.8, 15.12, 14.17, 13.20](https://aws.amazon.com/about-aws/whats-new/2025/02/amazon-rds-postgresql-supports-minor-versions/)
* [Amazon RDS for PostgreSQL supports minor versions 17.3, 16.7, 15.11, 14.16, 13.19](https://aws.amazon.com/about-aws/whats-new/2025/02/amazon-rds-for-postgresql-new-minor-versions/)

16.7 is already added at #33509.

### 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*

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

@@ -1633,6 +1633,10 @@ export class PostgresEngineVersion {
   public static readonly VER_13_17 = PostgresEngineVersion.of('13.17', '13', { s3Import: true, s3Export: true });
   /** Version "13.18". */
   public static readonly VER_13_18 = PostgresEngineVersion.of('13.18', '13', { s3Import: true, s3Export: true });
+  /** Version "13.19". */
+  public static readonly VER_13_19 = PostgresEngineVersion.of('13.19', '13', { s3Import: true, s3Export: true });
+  /** Version "13.20". */
+  public static readonly VER_13_20 = PostgresEngineVersion.of('13.20', '13', { s3Import: true, s3Export: true });
 
   /** Version "14" (only a major version, without a specific minor version). */
   public static readonly VER_14 = PostgresEngineVersion.of('14', '14', { s3Import: true, s3Export: true });
@@ -1690,6 +1694,10 @@ export class PostgresEngineVersion {
   public static readonly VER_14_14 = PostgresEngineVersion.of('14.14', '14', { s3Import: true, s3Export: true });
   /** Version "14.15". */
   public static readonly VER_14_15 = PostgresEngineVersion.of('14.15', '14', { s3Import: true, s3Export: true });
+  /** Version "14.16". */
+  public static readonly VER_14_16 = PostgresEngineVersion.of('14.16', '14', { s3Import: true, s3Export: true });
+  /** Version "14.17". */
+  public static readonly VER_14_17 = PostgresEngineVersion.of('14.17', '14', { s3Import: true, s3Export: true });
 
   /** Version "15" (only a major version, without a specific minor version). */
   public static readonly VER_15 = PostgresEngineVersion.of('15', '15', { s3Import: true, s3Export: true });
@@ -1717,6 +1725,10 @@ export class PostgresEngineVersion {
   public static readonly VER_15_9 = PostgresEngineVersion.of('15.9', '15', { s3Import: true, s3Export: true });
   /** Version "15.10". */
   public static readonly VER_15_10 = PostgresEngineVersion.of('15.10', '15', { s3Import: true, s3Export: true });
+  /** Version "15.11". */
+  public static readonly VER_15_11 = PostgresEngineVersion.of('15.11', '15', { s3Import: true, s3Export: true });
+  /** Version "15.12". */
+  public static readonly VER_15_12 = PostgresEngineVersion.of('15.12', '15', { s3Import: true, s3Export: true });
 
   /** Version "16" (only a major version, without a specific minor version). */
   public static readonly VER_16 = PostgresEngineVersion.of('16', '16', { s3Import: true, s3Export: true });
@@ -1734,13 +1746,19 @@ export class PostgresEngineVersion {
   public static readonly VER_16_6 = PostgresEngineVersion.of('16.6', '16', { s3Import: true, s3Export: true });
   /** Version "16.7" */
   public static readonly VER_16_7 = PostgresEngineVersion.of('16.7', '16', { s3Import: true, s3Export: true });
+  /** Version "16.8" */
+  public static readonly VER_16_8 = PostgresEngineVersion.of('16.8', '16', { s3Import: true, s3Export: true });
 
   /** Version "17" (only a major version, without a specific minor version). */
   public static readonly VER_17 = PostgresEngineVersion.of('17', '17', { s3Import: true, s3Export: true });
   /** Version "17.1". */
   public static readonly VER_17_1 = PostgresEngineVersion.of('17.1', '17', { s3Import: true, s3Export: true });
   /** Version "17.2". */
   public static readonly VER_17_2 = PostgresEngineVersion.of('17.2', '17', { s3Import: true, s3Export: true });
+  /** Version "17.3". */
+  public static readonly VER_17_3 = PostgresEngineVersion.of('17.3', '17', { s3Import: true, s3Export: true });
+  /** Version "17.4". */
+  public static readonly VER_17_4 = PostgresEngineVersion.of('17.4', '17', { s3Import: true, s3Export: true });
 
   /**
    * Create a new PostgresEngineVersion with an arbitrary version.