chore(rds): postgres add 17.7, 16.11, 15.15, 14.20, and 13.23 (#36053)

### Reason for this change
https://aws.amazon.com/about-aws/whats-new/2025/11/amazon-rds-postgres-sql-minor-versions/

### Description of changes
Postgres add 17.7, 16.11, 15.15, 14.20, and 13.23

### Description of how you validated changes
```console
$ aws rds describe-db-engine-versions --engine postgres --output table --query 'DBEngineVersions[*].{Engine:Engine,EngineVersion:EngineVersion}'
------------------------------------
|     DescribeDBEngineVersions     |
+-----------+----------------------+
|  Engine   |    EngineVersion     |
+-----------+----------------------+
...
|  postgres |  13.23               |
...
|  postgres |  14.20               |
...
|  postgres |  15.15               |
...
|  postgres |  16.11               |
...
|  postgres |  17.7                |
+-----------+----------------------+
```

### 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: phuhung273

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

@@ -1745,6 +1745,8 @@ export class PostgresEngineVersion {
   public static readonly VER_13_21 = PostgresEngineVersion.of('13.21', '13', { s3Import: true, s3Export: true });
   /** Version "13.22". */
   public static readonly VER_13_22 = PostgresEngineVersion.of('13.22', '13', { s3Import: true, s3Export: true });
+  /** Version "13.23". */
+  public static readonly VER_13_23 = PostgresEngineVersion.of('13.23', '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 });
@@ -1825,6 +1827,8 @@ export class PostgresEngineVersion {
   public static readonly VER_14_18 = PostgresEngineVersion.of('14.18', '14', { s3Import: true, s3Export: true });
   /** Version "14.19". */
   public static readonly VER_14_19 = PostgresEngineVersion.of('14.19', '14', { s3Import: true, s3Export: true });
+  /** Version "14.20". */
+  public static readonly VER_14_20 = PostgresEngineVersion.of('14.20', '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 });
@@ -1875,6 +1879,8 @@ export class PostgresEngineVersion {
   public static readonly VER_15_13 = PostgresEngineVersion.of('15.13', '15', { s3Import: true, s3Export: true });
   /** Version "15.14". */
   public static readonly VER_15_14 = PostgresEngineVersion.of('15.14', '15', { s3Import: true, s3Export: true });
+  /** Version "15.15". */
+  public static readonly VER_15_15 = PostgresEngineVersion.of('15.15', '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 });
@@ -1910,6 +1916,8 @@ export class PostgresEngineVersion {
   public static readonly VER_16_9 = PostgresEngineVersion.of('16.9', '16', { s3Import: true, s3Export: true });
   /** Version "16.10" */
   public static readonly VER_16_10 = PostgresEngineVersion.of('16.10', '16', { s3Import: true, s3Export: true });
+  /** Version "16.11" */
+  public static readonly VER_16_11 = PostgresEngineVersion.of('16.11', '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 });
@@ -1931,6 +1939,8 @@ export class PostgresEngineVersion {
   public static readonly VER_17_5 = PostgresEngineVersion.of('17.5', '17', { s3Import: true, s3Export: true });
   /** Version "17.6". */
   public static readonly VER_17_6 = PostgresEngineVersion.of('17.6', '17', { s3Import: true, s3Export: true });
+  /** Version "17.7". */
+  public static readonly VER_17_7 = PostgresEngineVersion.of('17.7', '17', { s3Import: true, s3Export: true });
 
   /**
    * Create a new PostgresEngineVersion with an arbitrary version.