GraphiQL is broken after release of 5.0 due to non-fixed unpgk link

[LukasKalbertodt]

Describe the bug
When using GraphiQL with the latest released Juniper (0.16.1), you get an endless loading screen as it tries to load https://unpkg.com/@graphiql/plugin-explorer/dist/index.umd.js which redirects to https://unpkg.com/@graphiql/plugin-explorer@5.0.0/dist/index.umd.js which is 404. This was caused by the release of @graphiql/plugin-explorer 5.0.0, which does not contain the file dist/index.umd.js.

To Reproduce
Setup a basic Juniper server with graphiql integration, i.e. juniper::http::graphiql::graphiql_source.

Expected behavior
GraphiQL should keep working regardless of whether new versions of packages are released. It would have been better if the link to unpkg contained a fixed version to begin with.

Additional context
This seems to be already solved on master by #1316 which changed the way external JS files are imported. So in theory, this just needs to be released as 0.16.2.

[tyranron]

@LukasKalbertodt yes. I'm planning to release 0.17.0 this or next week. There are only 2 PRs left, which are almost done and only require a little bit more polishing.