Update gltf-pipeline to 3.0.2

[ebogo1]

Updates gltf-pipeline to the latest version.

Should this target master instead? I believe there are two failing specs (embedded binary KTX/CRN textures) related to CesiumGS/gltf-pipeline#550 so I targeted the new ktx2-staging branch instead.

[cesium-concierge]

Thanks for the pull request @ebogo1!

• ✔️ Signed CLA found.
• ❔ Changes to third party files were made.
  • Looks like a file in one of our ThirdParty folders (ThirdParty/, Source/ThirdParty/) has been added or modified. Please verify that it has a section in LICENSE.md and that its license information is up to date with this new version.
• ❔ Unit tests were not updated.
  • Make sure you've updated tests to reflect your changes, added tests for any new code, and ran the code coverage tool.

Reviewers, don't forget to make sure that:

• Cesium Viewer works.
• Works in 2D/CV.
• Works (or fails gracefully) in IE11.

[lilleyse]

Should this target master instead?

I think it needs to target the staging branch otherwise KTX1 and CRN in glTF will break prior to us formally removing them (as you noted by the unit tests failing)

[lilleyse]

@ebogo1 it's also fine to delete the failing tests. At some point they'll need to be deleted, might as well be now so tests pass locally.

[ebogo1]

@lilleyse Should be ready once 893eadd passes; I removed the two failing specs and undid the CHANGES.md section.
edit - forgot to run eslint; should be good after b13f9ed.