publish.md

Refs:

• https://www.scala-sbt.org/release/docs/Using-Sonatype.html
• https://github.com/xerial/sbt-sonatype

One-time steps:

    > set pgpReadOnly := false
    > pgp-cmd gen-key
    > pgp-cmd send-key me@example.net hkp://pool.sks-keyservers.net

~/.sbt/version/sonatype.sbt:

credentials += Credentials("Sonatype Nexus Repository Manager",
                           "oss.sonatype.org",
                           "<your username>",
                           "<your password>")

Then:

    > package        
    > publishSigned        
    > sonatypeRelease