Regarding uploading same version + different build metadata, second upload will not create metadata in index.yaml
Steps to reproduce
1. create local helm repository
2. upload mychart-0.4.1+5.tgz using UI deploy button to a local-helm repository (successful to create metadata)
3. upload mychart-0.4.1+6.tgz using UI deploy button to a local-helm repository (fail to create metadata)
4. we were able to see mychart-0.4.1+5.tgz metadata in index.yaml. but were not able to see mychart-0.4.1+6.tgz metadata in index.yaml even though after recalculating metadata again.