Missing Meta files

[Peaj]

This issue might be similar to #214

I imported the package into a new Unity 2019.4.28f1 project which results in the following errors:

Asset Packages/com.proyecto26.restclient/packages.config has no meta file, but it's in an immutable folder. The asset will be ignored. 
(Filename: C:\buildslave\unity\build\Modules/AssetDatabase/Editor/V2/GuidDB.cpp Line: 625)

Asset Packages/com.proyecto26.restclient/Properties has no meta file, but it's in an immutable folder. The asset will be ignored. 
(Filename: C:\buildslave\unity\build\Modules/AssetDatabase/Editor/V2/GuidDB.cpp Line: 625)

Asset Packages/com.proyecto26.restclient/Properties/AssemblyInfo.cs has no meta file, but it's in an immutable folder. The asset will be ignored. 
(Filename: C:\buildslave\unity\build\Modules/AssetDatabase/Editor/V2/GuidDB.cpp Line: 625)

Asset Packages/com.proyecto26.restclient/Proyecto26.RestClient.csproj has no meta file, but it's in an immutable folder. The asset will be ignored. 
(Filename: C:\buildslave\unity\build\Modules/AssetDatabase/Editor/V2/GuidDB.cpp Line: 625)

Asset Packages/com.proyecto26.restclient/Proyecto26.RestClient.nuspec has no meta file, but it's in an immutable folder. The asset will be ignored. 
(Filename: C:\buildslave\unity\build\Modules/AssetDatabase/Editor/V2/GuidDB.cpp Line: 625)