Update README.md.

Author: shishir-a412ed

README.md

@@ -77,7 +77,7 @@ will launch the job.<br/>
 
 More detailed instructions are in the [`example README.md`](https://github.com/Roblox/nomad-driver-containerd/tree/master/example)
 
-## Supported options
+## Supported Options
 
 **Driver Config**
 
@@ -92,8 +92,8 @@ More detailed instructions are in the [`example README.md`](https://github.com/R
 
 Valid options for `containerd_runtime` (Driver Config).
 
-- `io.containerd.runc.v1`: runc runtime that supports a single container.
-- `io.containerd.runc.v2` (Default): runc runtime that supports multiple containers per shim.
+- `io.containerd.runc.v1`: `runc` runtime that supports a single container.
+- `io.containerd.runc.v2` (Default): `runc` runtime that supports multiple containers per shim.
 - `io.containerd.runsc.v1`: `gVisor` is an OCI compliant container runtime which provides better security than `runc`. They achieve this by implementing a user space kernel written in go, which implements a substantial portion of the Linux system call interface. For more details, please check their [`official documentation`](https://gvisor.dev/docs/)
 - `sysbox-runc`: `sysbox-runc` is another container runtime that runs a system container which will have system services like systemd (init system), docker, kubernetes already running inside that system container. This will allow you to have a container that is more akin to a VM, and you can launch other containers inside that system container. This also provides better security than `runc` as they run their system container in a user namespace and use shiftfs filesystem to shift UIDs/GIDs. For more details, please check their [`official documentation`](https://www.nestybox.com)
 
@@ -112,6 +112,7 @@ Valid options for `containerd_runtime` (Driver Config).
 | **seccomp** | bool | no | Enable default seccomp profile. List of [`allowed syscalls`](https://github.com/containerd/containerd/blob/master/contrib/seccomp/seccomp_default.go#L51-L395). |
 | **seccomp_profile** | string | no | Path to custom seccomp profile. `seccomp` must be set to `true` in order to use `seccomp_profile`. The default `docker` seccomp profile found [`here`](https://github.com/moby/moby/blob/master/profiles/seccomp/default.json) can be used as a reference, and modified to create a custom seccomp profile. |
 | **readonly_rootfs** | bool | no | Container root filesystem will be read-only. |
+| **runtime** | string | no | A string representing a configured runtime to pass to containerd. This is equivalent to the `--runtime` argument in the docker CLI. |
 | **host_network** | bool | no | Enable host network. This is equivalent to `--net=host` in docker. |
 | **extra_hosts** | []string | no | A list of hosts, given as host:IP, to be added to /etc/hosts. |
 | **cap_add** | []string | no | Add individual capabilities. |