kata-webhook-docs: Fix outdated script names

- Fix the instructions to add a different runtime class.
- Update script name that has underscore instead of dash.
- Remove dollar signs to make the commands copy pastable.

Fixes: kata-containers#5664

Signed-off-by: Suraj Deshmukh <suraj.deshmukh@microsoft.com>

kata-webhook/README.md

@@ -1,6 +1,6 @@
 # Kata Admission controller webhook
 
-Implement a simple admission controller webhook to annotate pods with the 
+Implement a simple admission controller webhook to annotate pods with the
 Kata runtime class.
 
 ## How to build the admission controller
@@ -17,7 +17,7 @@ controller.
 $ docker build -t quay.io/kata-containers/kata-webhook-example:latest -f Dockerfile .
 ```
 
-> **Note:**
+> **Note**
 > Image needs to be published for the webhook needs to work. Alternately
 > on a single machine cluster change the `imagePullPolicy` to use the locally
 > built image.
@@ -30,16 +30,19 @@ by default, except for workloads we know for sure will not work with Kata, use
 the [admission webhook](https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/#admission-webhooks)
 and sample admission controller we created by running the commands below:
 
-> **Note:**
+> **Note**
+>
 > By default, the `runtimeClass` name used in this webhook is `kata`. If your
 > cluster is configured with another `runtimeClass`, you'll need to change the
 > value of the `RUNTIME_CLASS` environment variable defined in the
-> [webhook file](deploy/webhook.yaml). You can manually edit the file or use
-> the `yq` tool. E.g:
-> `~/go/bin/yq w -i webhook.yaml spec.template.spec.containers[0].env[0].value "kata-clh"`
+> [webhook file](deploy/webhook.yaml). You can manually edit the file or run:
+>
+> `export RUNTIME_CLASS=<>`
+>
+> `kubectl create cm kata-webhook --from-literal runtime_class=$RUNTIME_CLASS`
 
 ```bash
-$ ./create_certs.sh
+$ ./create-certs.sh
 $ kubectl apply -f deploy/
 ```
 
@@ -51,8 +54,7 @@ $ ./webhook-check.sh
 ```
 
 The webhook mutates pods to use the Kata runtime class for all pods except
-those with 
+those with
 
-* `hostNetwork: true` 
+* `hostNetwork: true`
 * namespace: `rook-ceph` and `rook-ceph-system`
-