Document KubeVirt support

Signed-off-by: Roman Mohr <rmohr@redhat.com>

docs/supported-platforms.md

@@ -16,6 +16,7 @@ Ignition is currently only supported for the following platforms:
 * [Exoscale] (`exoscale`) - Ignition will read its configuration from the instance userdata. Cloud SSH keys are handled separately.
 * [Google Cloud] (`gcp`) - Ignition will read its configuration from the instance metadata entry named "user-data". Cloud SSH keys are handled separately.
 * [IBM Cloud] (`ibmcloud`) - Ignition will read its configuration from the instance userdata. Cloud SSH keys are handled separately.
+* [KubeVirt] (`kubevirt`) - Ignition will read its configuration from the instance userdata via config drive. Cloud SSH keys are handled separately.
 * Bare Metal (`metal`) - Use the `ignition.config.url` kernel parameter to provide a URL to the configuration. The URL can use the `http://`, `https://`, `tftp://`, `s3://`, or `gs://` schemes to specify a remote config.
 * [Nutanix] (`nutanix`) - Ignition will read its configuration from the instance userdata via config drive. Cloud SSH keys are handled separately.
 * [OpenStack] (`openstack`) - Ignition will read its configuration from the instance userdata via either metadata service or config drive. Cloud SSH keys are handled separately.
@@ -41,6 +42,7 @@ For most cloud providers, cloud SSH keys and custom network configuration are ha
 [Exoscale]: https://www.exoscale.com/compute/
 [Google Cloud]: https://cloud.google.com/compute
 [IBM Cloud]: https://www.ibm.com/cloud/vpc
+[KubeVirt]: https://kubevirt.io
 [Nutanix]: https://www.nutanix.com/products/ahv
 [OpenStack]: https://www.openstack.org/
 [Equinix Metal]: https://metal.equinix.com/product/