Add c.gh.debarshiray.toolbox to the container during 'podman create'

Commit 8127daa added the com.github.debarshiray.toolbox label
to the user-specific customized image generated by the 'create'
command, which gets inherited by toolbox containers using the image.
However, there might be really old images lying around in users' caches
that don't have the label, and in those cases the damage can be
limited by adding it directly to the newly created toolbox container.

Moreover, a subsequent commit will remove the need for the
user-specific customized image, and which will make this change
mandatory.

https://github.com/debarshiray/toolbox/pull/160

toolbox

@@ -925,6 +925,7 @@ create()
             $toolbox_path_set \
             --group-add wheel \
             --hostname toolbox \
+            --label "com.github.debarshiray.toolbox=true" \
             --name $toolbox_container \
             --network host \
             $no_hosts \