Jenkinsfile: Grab meta.yml as artifact as well

Jenkinsfile

 node {
    gitUrl = 'https://source.puri.sm/Librem5/image-builder.git'
    branch = 'master'
-   artifacts = "checksums,${params.board}.img.xz,tmp/*-report.log"
+   artifacts = "checksums,${params.board}.img.xz,tmp/*-report.log,files/meta.yml"
    build_on_x86 = [ 'imx6', 'qemu-x86_64' ]
    qcow2_builds = [ 'qemu-x86_64' ]
    currentBuild.description = "${params.board} ${params.dist} ${build_type} image"