Update Plugins
Update Plugins

+ Note regarding Guava version 20 and JDK 7 compatibility
~ "maven-surefire" to 2.20.1
~ "nexus-staging" to 1.6.8
~ "maven-gpg" to 1.6
~ "maven-source" to 3.0.1
~ "maven-javadoc" to 3.0.0-M1
- "plexus-archiver" dependency
thelinmichael/spotify-web-api-java,thelinmichael/spotify-web-api-java