change WrappedFunction & WrappedScheduledFunction's return type "any | Promise\<any>" to "T"
Problem
In the v0.3.3 wrap()() this function's return type will be any. so when I test promise function using by chai.should, Automatic completion doesn't work.
Following changes
Problem
In the v0.3.3![image](https://user-images.githubusercontent.com/48207131/149509066-cf083957-96c7-452e-8bcb-c6a4be7cbc2b.png)
wrap()()
this function's return type will be any. so when I test promise function using by chai.should, Automatic completion doesn't work.Solution
Return type
any | Promise<any>
must be any. So I use generic to "Promiseable" https://github.com/firebase/firebase-functions-test/blob/c1dd82b84f5fe4126ca666577a04a7d72e96f2fc/src/main.ts#L96-L99 change tothen I can use like that
![image](https://user-images.githubusercontent.com/48207131/149510721-d62239e6-d749-467e-bbfb-4715bb058f2d.png)