Setup

Add `.credentials` file under `~/.sbt/` folder with contents

realm=Sonatype Nexus Repository Manager
host=oss.sonatype.org
user=(USERNAME)
password=(PASSWORD_HERE)

Run sbt release to release signed both 2.10 and 2.11

sbt release

Then, git checkout v0.X.X to the release tag first, and then type

sbt sonatypeRelease

This will allow sonatype to release the artifacts to maven central.

An alternative is to browse to https://oss.sonatype.org and do it manually