Version latest released version as v1.0.0

[Dadadah]

When you download this repo with go get github.com/bwmarrin/snowflake go installs version v0.3.0 to your go.mod. Updating the tag on this repo will enable go to install the latest version instead, which you have to specify currently with v0.3.1-0.20190412223032-c09e69ae5993

The readme states this project is feature complete, and no breaking API changes will be introduced. That's why I suggest v1.0.0 for the current commit.

[bwmarrin]

Thanks for the suggestion - it's probably a good idea to make it 1.0