Add typings for stash-rest-api v2.6.0

[zergmk2]

Typings URL: https://github.com/zergmk2/typed-stash-rest-api

Questions (for new typings):

• Does the README explain the purpose of the typings and have a link to the JavaScript project?
• Do the typings follow the source structure (e.g. index.js <-> index.d.ts)?
• Are they external or global modules according the source (e.g. see README sources)?

Change Summary (for existing typings):
@felixfbecker
@blakeembrey
Sorry for my mistakenly closing the previous PR, I've updated my repo following your comments.
Could you please review it again? Thank you.

@zergmk2 You should use one from the registry ;)

I've used the "pinkie-promis" module from the registry instead of "promise" module.
https://github.com/zergmk2/typed-stash-rest-api/blob/master/src/index.d.ts#L1

Signed-off-by: Lu_Cao zergmk2@gmail.com

[blakeembrey]

@zergmk2 Sorry for the delay, you've got a typo importing pinkie-promise 😄 You may want to add some tests to make sure it compiles using TypeScript.