Add types declaration file

[JonnySpruce]

Resolves #77

This adds typescript support for this module, allowing you to use this for TypeScript projects. (Currently it will not compile as no types declaration can be found).

This also helps users that write only in JavaScript, since editors such as VS Code can use this declaration file to suggest properties that the user may want to access in returned objects, such as the results object.

I currently haven't added any tests to this - what are the thoughts on testing for this?

[coveralls]

Coverage remained the same at 100.0% when pulling f21e92b on JonnySpruce:add-types into 3582851 on adamreisnz:master.

[coveralls]

Coverage remained the same at 100.0% when pulling f21e92b on JonnySpruce:add-types into 3582851 on adamreisnz:master.

[coveralls]

Coverage remained the same at 100.0% when pulling f21e92b on JonnySpruce:add-types into 3582851 on adamreisnz:master.

[adamreisnz]

Thanks for putting this together. What exactly does it means that it won't compile yet, and will that impact TypeScript projects using this module?

I'd like to get another pair of 👀 on this from someone else to check/review before merging, will ask in the main thread.

[JonnySpruce]

I meant before this PR, if you require this module in a TypeScript project and have the no-implicit-any rule set to true, then the TypeScript project will not compile as it could not find types for this module. This PR resolves that issue.

There should be no impact to TypeScript projects currently using this module.

[adamreisnz]

Thanks, merged and released as 4.1.0 on npm