Update package search support to handle source dependencies

[cursive-ide]

In 1.12.0, Cursive now allows source dependencies to be specified in deps.edn files (#2591), and will download and attach them as sources. The Package Search integration doesn't understand this syntax, and should be updated to handle it.

[cursive-ide]

This is fixed in the next EAP. There are two parts - source artifacts are not returned to Package Search, so they will not appear in the dependencies window. Also, when a version of an artifact is updated, if there are source artifacts for that artifact at any level (either at root level or in an alias) the version of the source artifact will be updated too.