Podcasting 2.0 is a movement/initiative that’s all about decentralisation and enabling podcasters to do their work independently. I would certainly recommend to listen the Podcasting 2.0 podcast, which explains it all way better and in greater detail. (Simply find it in AntennaPod 
And I’d recommend to start with the first episode!)
Part of it is the Podcast Namespace, which is a an extension (namespace) to the RSS standard, allowing podcasters to include more information in their feeds. This information can then be used to create new podcasting apps/experiences. The Funding tag is just one of the extra types of information that can be included.
For those active in the Podcasting 2.0 community, this term is an important flag. Using it (rather than something like ‘crowdfunding’) hopefully helps with communication around AntennaPod coming along with the movement.