….2" (aws#30306)

### Issue # (if applicable)

Closes aws#30109 

### Reason for this change


Currently CDK does not show option to select the Engine version `3.04.2`


### Description of changes


Update the below class name to include "3.04.2"

```ts
export class AuroraMysqlEngineVersion {
public static readonly VER_3_04_2 = AuroraMysqlEngineVersion.builtIn_8_0('3.04.2');
}

```

### Description of how you validated changes


unit and integration 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)