Can't add `.env` for ini config

[stephentoub]

(Ported from @atrauzzi at https://github.com/dotnet/corefx/issues/11317)

If I use the following:

            var configuration = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddIniFile(".env")
                .Build()
            ;

I get:

Unhandled Exception: System.IO.FileNotFoundException: The configuration file '.env' was not found and is not optional.                                                                                  
   at Microsoft.Extensions.Configuration.FileConfigurationProvider.Load()                                                                                                                               
   at Microsoft.Extensions.Configuration.ConfigurationBuilder.Build()                                                                                                                                   
   at ConsoleApplication.Program.Main(String[] args)

Is there anything about the fact that the file starts with a dot that gets in the way here? Is there any reason why that should be a limitation?

[glennc]

On the face of it this is just a bug, we will get it assigned for investigation and fixing in the next triage. Which I think is tomorrow.

[HaoK]

Root issue appears to be the PhysicalFileProvider, filed: aspnet/FileSystem#232

[analogrelay]

Note to self and others, for clarification: This issue is not resolved in 1.1 because it is actually an issue in the PhysicalFileProvider. The relevant bug (referenced above) is currently not in the 1.1 milestone.