Fix interrupted numbering sequence in ubuntu installation docs

 - increase indent of note to match surrounding text

Signed-off-by: Morgan Bauer <mbauer@us.ibm.com>

docs/installation/ubuntulinux.md

@@ -127,12 +127,12 @@ install Docker using the following:
     The system prompts you for your `sudo` password. Then, it downloads and
     installs Docker and its dependencies.
 
->**Note**: If your company is behind a filtering proxy, you may find that the
->`apt-key`
->command fails for the Docker repo during installation. To work around this,
->add the key directly using the following:
->
->       $ wget -qO- https://get.docker.com/gpg | sudo apt-key add -
+    >**Note**: If your company is behind a filtering proxy, you may find that the
+    >`apt-key`
+    >command fails for the Docker repo during installation. To work around this,
+    >add the key directly using the following:
+    >
+    >       $ wget -qO- https://get.docker.com/gpg | sudo apt-key add -
 
 4. Verify `docker` is installed correctly.