Release Poptart v0.1.3

[wookay]

@JuliaRegistrator register()

[JuliaRegistrator]

Registration pull request created: JuliaRegistries/General/701

After the above pull request is merged, it is recommended that a tag is created on this repository for the registered package version.

This will be done automatically if Julia TagBot is installed, or can be done manually through the github interface, or via:

git tag -a v0.1.3 -m "<description of version>" 58388d7db727f1ce009c7474a8be894df3c5142d
git push origin v0.1.3