Fix contributor's field in nextflow.config

[grst]

Description of feature

According to the latest template, we are supposed to have a contributor field like

contributors    = [
        [name: "Alexander Peltzer", github: "apeltzer"],
        [name: "Christopher Mohr", github: "christopher-mohr"],
        [name: "Nicolás Schcolnicov", github: "nschcolnicov"],
        [name: "Anabella Trigila", github: "atrigila"],
        [name: "Alan Möbbs", github: "alanmmobbs93" ]
    ]
``

However this broke CI for one of the nextflow versions. I checked and it's not even updated in rnaseq or sarek, so let's wait until they figure that out properly in the community.