rename dnsplugin to dnsname

a user @Nuc1eoN pointed out a typo in the name in the readme.

Signed-off-by: Brent Baude <bbaude@redhat.com>

README.md

@@ -7,7 +7,7 @@ the pod and its IP address are added to a network specific hosts file that dnsma
 is removed from the network, it will remove the entry from the hosts file.  Each CNI network will have its own dnsmasq
 instance.
 
-The *dnsplugin* plugin was specifically designed for the [Podman](https://github.com/containers/libpod) container engine.
+The *dnsname* plugin was specifically designed for the [Podman](https://github.com/containers/libpod) container engine.
 Follow the [mini-tutorial](README_PODMAN.md) to use it with Podman.