Resolve colliding file names on case-insensitive file systems

When cloning this repo on Windows I get:

```
warning: the following paths have collided (e.g. case-sensitive paths
on a case-insensitive filesystem) and only one from the same
colliding group is in the working tree:

'curations/nuget/nuget/-/DiscUtils.yaml'
'curations/nuget/nuget/-/Discutils.yaml'
'curations/nuget/nuget/-/EMGU.CV.yaml'
'curations/nuget/nuget/-/Emgu.CV.yaml'
'curations/nuget/nuget/-/GitLink.yaml'
'curations/nuget/nuget/-/gitlink.yaml'
'curations/nuget/nuget/-/Microsoft.AspNetCore.Authentication.JwtBearer.yaml'
'curations/nuget/nuget/-/microsoft.aspnetcore.authentication.jwtbearer.yaml'
'curations/nuget/nuget/-/MSBuildTasks.yaml'
'curations/nuget/nuget/-/MsBuildTasks.yaml'
'curations/nuget/nuget/-/React.Core.yaml'
'curations/nuget/nuget/-/react.core.yaml'
'curations/nuget/nuget/-/StructureMap.yaml'
'curations/nuget/nuget/-/structuremap.yaml'
'curations/nuget/nuget/-/System.Data.HashFunction.SpookyHash.yaml'
'curations/nuget/nuget/-/system.data.hashfunction.spookyhash.yaml'
'curations/nuget/nuget/-/System.Windows.Interactivity.WPF.yaml'
'curations/nuget/nuget/-/system.windows.interactivity.wpf.yaml'
'curations/nuget/nuget/-/TinyMCE.JQuery.yaml'
'curations/nuget/nuget/-/TinyMCE.jQuery.yaml'
'curations/nuget/nuget/-/ValueInjecter.yaml'
'curations/nuget/nuget/-/valueinjecter.yaml'
'curations/nuget/nuget/-/VsWhere.yaml'
'curations/nuget/nuget/-/vswhere.yaml'
'curations/pypi/pypi/-/Pillow.yaml'
'curations/pypi/pypi/-/pillow.yaml'
'curations/pypi/pypi/-/Resource.yaml'
'curations/pypi/pypi/-/resource.yaml'
```

I believe the contents of these pairs of files should be merged, and the capitalization should be aligned to the spelling used in the respective registry. Would you agree with that rationale @capfei @fossygirl?

Start by comparing the colliding YAML pairs under curations/nuget/nuget/- and curations/pypi/pypi/- listed in the issue, then check each package's spelling in its registry. Done means the pair contents are merged, each filename uses the registry's capitalization, and the repository no longer reports collisions on case-insensitive filesystems.

Written by the indexing model from the issue text.