Metadata schema links are broken

### Description

The links on [the metadata examples page](https://github.com/GSA/code-gov/blob/master/docs/metadata_examples.md) that purport to link to the schema definition, in fact simply link to general code.gov information.  These should link to the schema definition.

In the meantime, does anyone have a link to the schema definition?  I would appreciate it.