PHP-SDK - 3.2.0

## 3.2.0
August 28th, 2019

### New Features:
* Added support for datafile management via [HTTPProjectConfigManager](https://github.com/optimizely/php-sdk/blob/master/src/Optimizely/ProjectConfigManager/HTTPProjectConfigManager.php):
* The [HTTPProjectConfigManager](https://github.com/optimizely/php-sdk/blob/master/src/Optimizely/ProjectConfigManager/HTTPProjectConfigManager.php) is an implementation of the [ProjectConfigManagerInterface](https://github.com/optimizely/php-sdk/blob/master/src/Optimizely/ProjectConfigManager/ProjectConfigManagerInterface.php).
* Users will have to initialize and pass in the config manager to be able to use it:
```
$configManager = new HTTPProjectConfigManager(<>);
$optimizely = new Optimizely(<>, null, null, null, false, null, $configManager);
```
* The `fetch` method allows you to refresh the config. In order to update the config, you can do something like:
```
$configManager->fetch();
```


https://github.com/optimizely/php-sdk/releases/tag/3.2.0