New console template – use user secret

1. dotnet user-secrets init
2. set a secret: dotnet user-secrets set “API_KEY” “test123”
3. use UserSecretsId (from .csproj file) in AddUserSecrets()

IConfiguration configuration = new ConfigurationBuilder()
    .AddUserSecrets("d9a5cd4e-7c74-46da-a5d5-7321a7d4ae95")
    .Build();

var key = configuration["API_KEY"];