db.Connection.CreateMany should set IDs

[dqu123]

What happened:

What you expected to happen:
IDs to be set in array of objects after calling CreateMany()

How to reproduce it (as minimally and precisely as possible):
CreateMany() any array of objects. Print out the IDs, which will remain 0.

Anything else we need to know?:
https://stackoverflow.com/a/5876411 seems to provide a solution:
INSERT INTO my_table VALUES ('a'), ('b'), ('c') RETURNING id;

Environment:

• go-sdk version: v1.1.1

• go version (e.g go version): go version go1.12.12 darwin/amd64

• OS (e.g: cat /etc/os-release): uname -mrsv -> Darwin 18.6.0 Darwin Kernel Version 18.6.0: Thu Apr 25 23:16:27 PDT 2019; root:xnu-4903.261.4~2/RELEASE_X86_64 x86_64

• Others: