License for future releases?

[ashwinvis]

Since this is a simple project, something permissive like Apache 2.0 would be enough. It has additional plus points like being compatible with GPL v3.

This is a free software license, compatible with version 3 of the GNU GPL.
Please note that this license is not compatible with GPL version 2, because it has some requirements that are not in that GPL version. These include certain patent termination and indemnification provisions. The patent termination provision is a good thing, which is why we recommend the Apache 2.0 license for substantial programs over other lax permissive licenses.

from https://www.gnu.org/licenses/license-list.html

[ashwinvis]

I also recommend whatever license we choose here to be applied on suan/instant-markdown-d as well.

[ashwinvis]

Quoting @suan from an email conversation:

Yup, I think the Apache license would be fine. Thanks for taking that on!