@ronnyandre I just released version 1.3.0 with a Loki adapter added. You can use loki://<loki_host>:3100 as route.
I did find this Promptail addon however, which should also work for Loki (there is also a Loki addon by the way which I used for testing). The promptail addon might work better for you (or not). It has at least one advantage: is doesn’t require protection mode to be disabled because it mounts the journald logs.
Even when you decide to use the promptail addon however I would still appreciate it if you would give this adapter a try and give some feedback.