Review licenses for vendored libraries / creation of `CREDITS.html`

Creating follow-on issue from initial feedstock submission:

https://github.com/conda-forge/staged-recipes/pull/12747#issuecomment-737376461

> it would be perfect to have a 1-1 match to all vendored parts and the corresponding licensing. With that said, done is better than perfect. Let's merge this so you can move ahead but please open an issue in the feedstock so we can look further if we got them all or if we need to specify any missing licenses.

My understanding of the situation:

- The kaleido-core feedstock implicitly vendors chromium and the third-party libraries that are compiled into Chromium.
- It does not vendor any other libraries.
- The chromium codebase provides a script that generates a large `CREDITS.html` file should contain the license information for all of the third-party libraries that it contains.
- Originally, kaleido ran this script to generate the `CREDITS.html` file. But during the review processes, it was noticed that this `CREDITS.html` file didn't contain references to the vulkan libraries that are included on MacOs. The `CREDITS.html` file that ships with current versions of Chromium (accessible from a chromium browser by opening `chrome://credits/`) does contain references to vulkan. For expediency, the `CREDITS.html` shipped with kaleido was updated to a version obtained this way.

Ideally, we would get to the bottom of why vulkan was left out of the automated `CREDITS.html` build. e.g. Perhaps it was a bug that it was excluded in the version of the script that shipped with the build of Chromium that Kaleido currently uses.

cc @isuruf @ocefpaf