First, do not worry, the YouTube Player is not being decommissioned. PhantomBot will just no longer be providing a key in the PhantomBot release.
Unfortunately, due to the current key being used, or perhaps misused, as we are seeing over 4 million queries a day, YouTube is rejecting all queries after we pass our quota (which is lasting about 3 hours). This started on December 13th. Before that we saw traffic that appeared to be more normal:
Because of this, we are no longer providing a key with the PhantomBot release. Users will be required to obtain their own YouTube API key. The instructions to do this are on the Community Forum:
The current API key has already been disabled and will be deleted. To continue to use the YouTube Player currently, you will also need to acquire your own key. We apologize for the inconvenience that this may cause.
As of the PhantomBot Nightly Build (2018 Dec 18), the key will no longer be included with the distribution. A new error pop-up will be provided in the YouTube Player if a YouTube Key is not configured: