Add GDPR support for Quantcast adapter

[soarez]

Type of change

• Bugfix
• Feature
• New bidder adapter
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Does this change affect user-facing APIs or examples documented on http://prebid.org?
• Other

Description of change

Following up on #2549 (please close), this adds GDPR support for the Quantcast adapter.

• test parameters for validating bids

{
    bidder: 'quantcast',
    params: {
        publisherId: 'test-publisher', // REQUIRED - Publisher ID provided by Quantcast
        battr: [1, 2] // OPTIONAL - Array of blocked creative attributes as per OpenRTB Spec List 5.3
    }
}

Be sure to test the integration with your adserver using the Hello World sample page.

• contact email of the adapter’s maintainer: igor.soarez@quantcast.com
• official adapter submission

For any changes that affect user-facing APIs or example code documented on http://prebid.org, please provide:

• A link to a PR on the docs repo: gdpr enabled in https://github.com/erolosty/Prebid.js/commit/4196b9f6… prebid.github.io#768

[bretg]

@soarez - please fix build error

[harpere]

LGTM