I just cloned the project to mvn clean install
At first I had to change maven-compiler-plugin source and target from 1.6 to 1.7 as 1.6 is no longer supported.
Now I am getting the exception while trying to install.

Failed to execute goal org.apache.maven.plugins:maven-gpg-plugin:1.6:sign (sign-artifacts) on project metadata-extractor: Exit code: 2 ->