Misuse or incorrect type for aws_credentials_provider:options()

[dw-kihara]

Hello,

I am trying to use this library and I found a problem with aws_credentials_provider:options().

According to the type declaration this type appear to be a nested map as shown below:

%% type declaration in aws_credentials_provider
%% -type options() :: #{provider() => map()}.

%% maybe like this
Options = #{
    aws_credentials_file => #{
        credential_path => "/path/to/aws/",
        profile => "my_profile"
    }
}.

However, in practice, the variable needs to be a flat map without a provider name, as shown in this example:

%% code in aws_credentials_file
-spec get_file_path(aws_credentials_provider:options()) -> {error, any()} | string().
get_file_path(Options) ->
  case maps:get(credential_path, Options, undefined) of
    undefined -> maybe_add_home("/.aws/");
    Path -> Path
  end.

Possible fixes:

1. Keep the current code and modify aws_credentials_provider:options() type to be a flat map to match current usage.
2. Change option values and usage to match the type declaration.

Method 1 is easier but makes it much harder to have different options for different providers in the future.
Method 2 is cleaner but breaks current library users, though some compatibility compromises could be made.

If I could choose, I would take method 2 with special credentials_path and profile options to maintain compatibility for current aws_credentials_file users.
(Luckily, there are no other usage except for those two options in aws_credentials_file.)

Thank you!