Hello,
https://github.com/SonarQubeCommunity/sonar-erlang is/was managed by the SonarQube community more precisely by Tamás Kende. In March 2018, Tamas asked to SonarSource to remove the plugin out of the Marketplace because he will have no time to continue to maintain it. See https://groups.google.com/forum/#!searchin/sonarqube/erlang|sort:date/sonarqube/tnByTHWrdDg/mRek_YvVAQAJ
So as of now, sonar-erlang is looking for a maintainer and I have no idea in which state it is.
You can try and download the latest version here: https://github.com/SonarQubeCommunity/sonar-erlang/releases and see if it is working with SonarQube 6.7+
Download the JAR, put it in your $SQ_HOME/extensions/plugins directory and restart SonarQube.
Then run a “sonar-scanner” command like you would do for any other languages such as PHP for example: https://docs.sonarqube.org/display/PLUG/SonarPHP
SonarSource is having no plan to take the lead on sonar-erlang, so if you want to jump it, you would be more than welcome.
Regards