Add aws-lambda-java-events-sdk-transformer library with DynamodbEvent v2.2.8 support

[carlzogh]

Description of changes:
This change adds a new library aws-lambda-java-events-transformer to the collection.

Extract from Readme:

About

Provides helper classes/methods to use alongside aws-lambda-java-events in order to transform Lambda input event model objects into SDK-compatible output model objects (eg. DynamodbEvent to a List of records writable back to DynamoDB through the AWS DynamoDB SDK v2).

Getting started

Add the following Apache Maven dependencies to your pom.xml file:

<dependencies>
    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-lambda-java-events-sdk-transformer</artifactId>
        <version>1.0.0</version>
    </dependency>
    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-lambda-java-events</artifactId>
        <version>2.2.8</version>
    </dependency>
</dependencies>

To use this library as a transformer to the AWS DynamoDB Java SDK v2, also add the following dependencies to your pom.xml file:

<dependencies>
    <dependency>
        <groupId>software.amazon.awssdk</groupId>
        <artifactId>dynamodb</artifactId>
        <version>2.11.12</version>
    </dependency>
    <dependency>
        <groupId>com.amazonaws</groupId>
        <artifactId>aws-java-sdk-dynamodb</artifactId>
        <version>1.11.163</version>
    </dependency>
</dependencies>

Note that because aws-lambda-java-events version 2 requires the DynamoDB v1 SDK, this is also required for this library.

Example Usage

To convert a full DynamodbEvent object to an SDK v2 compatible List<Record>:

import com.amazonaws.services.lambda.runtime.events.transformers.DynamodbEventTransformer;
public class DDBEventProcessor implements RequestHandler<DynamodbEvent, String> {
    public String handleRequest(DynamodbEvent ddbEvent, Context context) {
        // Process input event
        List<Record> convertedRecords = DynamodbEventTransformer.toRecordsV2(ddbEvent);
        // Modify records as needed and write back to DynamoDB using the DynamoDB AWS SDK for Java 2.0
    }
}

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.