Unity have released a statement about their approach to GDPR:
According to this page, from May 25 they will embed consent controls directly inside Unity Ads:
How will Unity allow players to decide if they receive targeted ads?
They go on to say that this functionality will automatically become available if Unity Ads SDK 2.0 or newer is used:
As a publisher, do I need to update my Unity Ads SDK?
If you are using Unity Ads SDK 2.0 or newer, GDPR-related changes will be automatically available to you no later than May 25, 2018. If you are using SDK 1.5 or older, we recommend that you update the SDK; otherwise, Unity can only serve contextual ads for your players.
This Corona forum post suggests that Corona is already using SDK 2.0 or later:
So it seems that these changes should apply automatically to Corona apps using the Unity Ads plugin, with no further SDK or plugin update needed. Is this the case?