Update README.md

Added a title for data sources.  Sort of tongue in cheek but I did end up here and would love to see this info upfront :)

Author: jameshowison

README.md

@@ -16,7 +16,8 @@ Here is an earlier iteration built using Kumu. We want to build something simila
  - [kumu instance](https://embed.kumu.io/6cbeee6faebd8cc57590da7b83c4d457#default)
  - [demo video](https://www.youtube.com/watch?v=jZyLSRCba_M)
 
+## Data Sources
 
 ## Contributing
 We are using the [fork and pull](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/getting-started/about-collaborative-development-models#fork-and-pull-model) collaborative development model, we welcome [pull requests](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request-from-a-fork). 
-- Check issues for anything to work on
+- Check issues for anything to work on