Fix stacked versions of dependencies.

[ProjectSynchro]

Currently I did a bunch of hackery to get single JSON files for each project being built.

This means a custom JSON merging script, and a shitload of invocations of the flatpak-dotnet-generator.py script.
The JSON merging script makes the JSON not readable at all without some beautification.

Ideally multiple csproj files could be passed into flatpak-dotnet-generator.py at once to only have to call the generator once per repository and get a single json file every time. without the other stuff.

This particularily is handy for the plugins as they each have csproj files.

[ProjectSynchro]

flatpak/flatpak-builder-tools#206 looks like the solution to this.

[ProjectSynchro]

Should be fixed as of 71c335f