Document override-arch and override-os

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

docs/source/markdown/podman-create.1.md

@@ -599,6 +599,12 @@ Whether to disable OOM Killer for the container or not.
 
 Tune the host's OOM preferences for containers (accepts -1000 to 1000)
 
+**--override-arch**=*ARCH*
+Override the machine's default architecture of the image to be pulled. For example, `arm`.
+
+**--override-os**=*OS*
+Use OS instead of the running OS for choosing images
+
 **--pid**=*pid*
 
 Set the PID mode for the container