chore(rds): add MariaDB version 10.4.34, 10.5.25, 10.6.18, 10.11.8 (#30579)

Add new MariaDB version for RDS.

[Amazon RDS for MariaDB supports minors 10.11.8, 10.6.18, 10.5.25, 10.4.34
](https://aws.amazon.com/about-aws/whats-new/2024/06/amazon-rds-mariadb-supports-new-minors/)

```sh
% aws rds describe-db-engine-versions --engine mariadb --query "DBEngineVersions[?EngineVersion=='10.11.8'||EngineVersion=='10.6.18'||EngineVersion=='10.5.25'||EngineVersion=='10.4.34'].[DBEngineVersionDescription,EngineVersion,DBParameterGroupFamily,MajorEngineVersion,Status]"

[
    [
        "MariaDB 10.4.34",
        "10.4.34",
        "mariadb10.4",
        "10.4",
        "available"
    ],
    [
        "MariaDB 10.5.25",
        "10.5.25",
        "mariadb10.5",
        "10.5",
        "available"
    ],
    [
        "MariaDB 10.6.18",
        "10.6.18",
        "mariadb10.6",
        "10.6",
        "available"
    ],
    [
        "MariaDB 10.11.8",
        "10.11.8",
        "mariadb10.11",
        "10.11",
        "available"
    ]
]
```

### 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: mazyu36

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

@@ -426,6 +426,8 @@ export class MariaDbEngineVersion {
   public static readonly VER_10_4_32 = MariaDbEngineVersion.of('10.4.32', '10.4')
   /** Version "10.4.33". */
   public static readonly VER_10_4_33 = MariaDbEngineVersion.of('10.4.33', '10.4');
+  /** Version "10.4.34". */
+  public static readonly VER_10_4_34 = MariaDbEngineVersion.of('10.4.34', '10.4');
 
   /** Version "10.5" (only a major version, without a specific minor version). */
   public static readonly VER_10_5 = MariaDbEngineVersion.of('10.5', '10.5');
@@ -478,6 +480,8 @@ export class MariaDbEngineVersion {
   public static readonly VER_10_5_23 = MariaDbEngineVersion.of('10.5.23', '10.5');
   /** Version "10.5.24". */
   public static readonly VER_10_5_24 = MariaDbEngineVersion.of('10.5.24', '10.5');
+  /** Version "10.5.25". */
+  public static readonly VER_10_5_25 = MariaDbEngineVersion.of('10.5.25', '10.5');
 
   /** Version "10.6" (only a major version, without a specific minor version). */
   public static readonly VER_10_6 = MariaDbEngineVersion.of('10.6', '10.6');
@@ -512,6 +516,8 @@ export class MariaDbEngineVersion {
   public static readonly VER_10_6_16 = MariaDbEngineVersion.of('10.6.16', '10.6');
   /** Version "10.6.17". */
   public static readonly VER_10_6_17 = MariaDbEngineVersion.of('10.6.17', '10.6');
+  /** Version "10.6.18". */
+  public static readonly VER_10_6_18 = MariaDbEngineVersion.of('10.6.18', '10.6');
 
   /** Version "10.11" (only a major version, without a specific minor version). */
   public static readonly VER_10_11 = MariaDbEngineVersion.of('10.11', '10.11');
@@ -523,6 +529,8 @@ export class MariaDbEngineVersion {
   public static readonly VER_10_11_6 = MariaDbEngineVersion.of('10.11.6', '10.11');
   /** Version "10.11.7". */
   public static readonly VER_10_11_7 = MariaDbEngineVersion.of('10.11.7', '10.11');
+  /** Version "10.11.8". */
+  public static readonly VER_10_11_8 = MariaDbEngineVersion.of('10.11.8', '10.11');
 
   /**
    * Create a new MariaDbEngineVersion with an arbitrary version.