Load JSON-serialized configurations from environment variables

This package has all the goodness in both Microsoft.Extensions.Configuration.EnvironmentVariables (reads environment variables) and Microsoft.Extensions.Configuration.Json (parses variable as JSON stream) from aspnet/Configuration.

As a result you can write

var config = new ConfigurationBuilder()
                .AddJsonEnvironmentVariables("CI_BUILD_SETTINGS")
                .Build();

var testSettings = config.GetSection("Tests").Get<TestSettings>();

Check the ASP.NET Core 2.1 app in sample project.

Run it for the first time without providing any extra configuration:

$ dotnet run
info: Sample.Startup[0]
      ["foo:bar"] = baz

And once with APP_SETTINGS environment variable with a JSON-serialized value:

$ APP_SETTINGS='{"foo":{"bar":"quz"}}' dotnet run
info: Sample.Startup[0]
      ["foo:bar"] = quz

This time the value(quz) in our environment variable overrides the default baz.