[BREAKING CHANGE] public class Microsoft.Extensions.FileProviders.FileSystemInfoHelper was made static

[javiercn]

V1:
public class FileSystemInfoHelper
V2:
public static class FileSystemInfoHelper

[ACTION for 1.1]: Undo the breaking change.
[ACTION for 2.0]: Make the class internal.

[javiercn]

@Eilon @muratg

[natemcmaster]

Mea culpa. 0e21803

[Eilon]

No biggie, let's just make it un-static and we'll fix it in 2.0.