Drop support for Node.js 0.12

[LinusU]

Node.js 0.12 is officially unsupported and we should drop support in the next major version

related: #414

[jimthedev]

Closed by d0772db, right @LinusU?

[LinusU]

Yes, should we close now or when merging v3.x to master?

[jimthedev]

When we merge into master.

[jimthedev]

@LinusU fwi I've added this and other issues to an organization-wide project here: https://github.com/orgs/commitizen/projects/1

You don't need to use it but I wanted you to know it exists.

[LinusU]

Nice!

[OmgImAlexis]

This can be closed.