Dockefile: remove udevadm missing warning

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

Dockerfile

@@ -16,6 +16,7 @@ FROM ubuntu
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get -y install --no-install-recommends \
         util-linux \
+        udev \
         parted \
         e2fsprogs \
         mount \

examples/ubuntu.Dockerfile

@@ -1,4 +1,4 @@
 FROM ubuntu
 
 RUN apt update && apt install -y openssh-server && \
-    echo "PermitRootLogin yes" >> /etc/ssh/sshd_config \
+    echo "PermitRootLogin yes" >> /etc/ssh/sshd_config