aws sdk for php v3

まずcomposerをいれます。

$ curl -sS https://getcomposer.org/installer | php

続いて、aws sdkをinstallします。

$ composer require aws/aws-sdk-php
Using version ^3.62 for aws/aws-sdk-php
./composer.json has been created
Loading composer repositories with package information
Updating dependencies (including require-dev)
Package operations: 6 installs, 0 updates, 0 removals
  - Installing mtdowling/jmespath.php (2.4.0): Downloading (100%)
  - Installing psr/http-message (1.0.1): Loading from cache
  - Installing guzzlehttp/psr7 (1.4.2): Loading from cache
  - Installing guzzlehttp/promises (v1.3.1): Loading from cache
  - Installing guzzlehttp/guzzle (6.3.3): Downloading (100%)
  - Installing aws/aws-sdk-php (3.62.2): Downloading (100%)
guzzlehttp/guzzle suggests installing psr/log (Required for using the Log middleware)
aws/aws-sdk-php suggests installing doctrine/cache (To use the DoctrineCacheAdapter)
aws/aws-sdk-php suggests installing aws/aws-php-sns-message-validator (To validate incoming SNS notifications)
Writing lock file
Generating autoload files