syslog: change it to unix domain socket

docker is using a extra udp port for every container. when there is
a lot of containers, a lot of random udp ports get used up. this causes
problems when installing apps that require contiguous port ranges

src/infra_version.js

@@ -6,7 +6,7 @@
 
 exports = module.exports = {
     // a version change recreates all containers with latest docker config
-    'version': '49.5.0',
+    'version': '49.6.0',
 
     // a major version bump in the db containers will trigger the restore logic that uses the db dumps
     // docker inspect --format='{{index .RepoDigests 0}}' $IMAGE to get the sha256