ci: Update mqttdpms Jenkins project name

I've switched Jenkins to use a Gitea Organization Folder so it can
auto-discover repositories owned by my Gitea user.  This naturally
required the paths of existing projects to change.  Here, we're updating
the path to the *mqttdpms* project to reflect its new location.

ci/Jenkinsfile

@@ -12,7 +12,7 @@ pipeline {
         buildDiscarder logRotator(numToKeepStr: '5')
         disableConcurrentBuilds()
     }
-   
+
     triggers {
         pollSCM ''
     }
@@ -41,7 +41,7 @@ pipeline {
                 }
                 copyArtifacts \
                     filter: 'aarch64/mqttdpms',
-                    projectName: 'mqttdpms/master',
+                    projectName: '../mqttdpms/master',
                     selector: lastSuccessful()
                 sh 'install aarch64/mqttdpms overlay/usr/local/bin/'
                 sh 'make rootfs initramfs'