fixed signRegion setting for far east endpoints

[77web]

Hi, signRegion for far east region is us-west-2 not eu-west-1.
https://developer.amazon.com/docs/incentives-api/incentives-api.html#endpoints

We need valid signRegion for far east endpoint.
Thanks in advance.

[stof]

Thanks for catching this, and sorry for the mistake (as you can guess, our own usage at Incenteev does not use that region).

However, modifying this method directly is the wrong way to fix it as it is part of the code generated using async-aws/code-generator. Instead, the value must be modified in the manifest file (manifest/endpoints.json in this case) and the code regenerated by using ./generate --all.

Sorry for not having contribution guidelines about that. I did not really expect receiving external contributions for that package so I haven't written them yet. It is nice to know that this package is benefiting others though (that's the reason we open-sourced it instead of keeping it as a private package).

[77web]

@stof
Thank you!
I've updated manifest and executed generate 😃

[stof]

Thank you @77web.