Support Yii 2.0.15 and PHP 7.2

Upgrade to PHP 7.2 and Yii 2.0.15. (#31)

Upgrade to Yii 2.0.13

Add compatibility with Yii 2.0.13. (#30)

* Add compatibility with Yii 2.0.13.

* Upgrade compatibility to 7.2.

* Upgrade AWS SDK compatibility to 7.2.

* Fix AWS required version.

* Downgrade to 7.1.

* Fix README.

Upgrade Yii2 and AWS SDK requirement

Merge pull request #22 from setyolegowo/master

Fix PHP SDK int|string issue

1.0.1: Retain AWS SDK 2.8

Merge pull request #19 from setyolegowo/activerecord-test

Fix NULL object access in ActiveDataProvider

Release 1.0.0

New Yii2 DynamoDB extension.

0.9

Unstable version.