Specifying executable names in DUB

[Dave]

Greetings,

This might be totally obvious, but I can't seem to figure out how 
to specify an executable's name&path to be different for each 
build types in my DUB package. For example, if my project is 
named "dlang_test", I might want something like so:

dub build --build=debug

yields either

bin/dlang_test-debug.exe

or possibly

bin/debug/dlang_test.exe

if I did

dub build --build=release

I might get either

bin/dlang_test-release.exe

or

bin/release/dlang_test.exe

When I read the section on build types 
(https://dub.pm/package-format-json.html#build-types), it 
specifically mentions that a "buildTypes" entry can override the 
build settings, but *not* "targetName" and "targetPath", which is 
what I think I want here.

Is there any reason why this is disallowed? Or is there a more 
canonical way of achieving this with DUB? What I described above 
is often found in other build tools, such as CMake and Visual 
Studio, which makes me think I'm missing something obvious here.

Thanks!