feat: replace SOURCES.md with datapackage.md (#643)

Co-authored-by: Dan Redding <[email protected]>

README.md

@@ -8,7 +8,9 @@ Collection of datasets used in Vega and Vega-Lite examples. This data lives at h
 
 Common repository for example datasets used by Vega related projects. Keep changes to this repository minimal as other projects (Vega, Vega Editor, Vega-Lite, Polestar, Voyager) use this data in their tests and for examples.
 
-The list of sources is in [SOURCES.md](https://github.com/vega/vega-datasets/blob/next/SOURCES.md).
+The list of sources is in [datapackage.md](https://github.com/vega/vega-datasets/blob/next/datapackage.md#resources).
+This metadata is also available in a machine-readable format at [datapackage.json](https://github.com/vega/vega-datasets/blob/next/datapackage.json).
+
 
 To access the data in Observable, you can import `vega-dataset`. Try our [example notebook](https://observablehq.com/@vega/vega-datasets). To access these datasets from Python, you can use the [Vega datasets python package](https://github.com/altair-viz/vega_datasets). To access them from Julia, you can use the [VegaDatasets.jl julia package](https://github.com/davidanthoff/VegaDatasets.jl).
 

_data/templates/package-table.md

@@ -0,0 +1,15 @@
+# {{ package.name }}
+`{{ package.version }}` | [GitHub]({{ package.homepage }}) | {{ package.created  | fmt_date()}}
+
+{{ package.description }}
+
+## licenses
+{{ package.licenses | tabulate() }}
+
+## contributors
+{{ package.contributors | tabulate() }}
+
+# resources
+{% for resource in package.resources %}
+  {% include 'resource-table.md' %}
+{% endfor %}

_data/templates/resource-table.md

@@ -0,0 +1,23 @@
+## `{{ resource.name }}`{% if resource.title %} {{ resource.title }}{% endif %}
+
+{% if resource.path %}
+### path
+{{ resource.path }}
+{% endif %}
+{% if resource.description %}
+### description
+{{ resource.description }}
+{% endif %}
+{% if resource.schema %}
+### schema
+{{ resource.schema | filter_dict(exclude=['fields']) | dict_to_markdown(level=2) }}
+{{ resource.schema.fields | tabulate() }}
+{% endif %}
+{% if resource.sources %}
+### sources
+{{ resource.sources | tabulate() }}
+{% endif %}
+{% if resource.licenses %}
+### licenses
+{{ resource.licenses | tabulate() }}
+{% endif %}