Added support for the Digikey Marketplace API

[fpgadeveloper]

Hi,

Thanks for this good work. I needed the Digikey Marketplace API, so by following your model and using your API generator, I added it to the package. I've tested it and it all works (order retrieval, order acceptance, order shipping). I don't know if your intention was to expand this package to (eventually) support all of the Digikey APIs (not just search), but I'm making this pull request in case you were. If that's not your intention, that's OK, I'll just maintain this in parallel.

Thanks again, you've saved me a lot of work!

Jeff

[peeter123]

Thanks Jeff, will look into this and merge it in a later version!