[stable/external-dns] Adapt docs to Helm 3 (#20683)

Signed-off-by: Carlos Rodriguez Hernandez <crhernandez@bitnami.com>

stable/external-dns/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v1
 name: external-dns
-version: 2.16.1
+version: 2.16.2
 appVersion: 0.5.18
 description: ExternalDNS is a Kubernetes addon that configures public DNS servers with information about exposed Kubernetes services to make them discoverable.
 keywords:

stable/external-dns/README.md

@@ -5,7 +5,7 @@
 ## TL;DR;
 
 ```console
-$ helm install stable/external-dns
+$ helm install my-release stable/external-dns
 ```
 
 ## Introduction
@@ -24,7 +24,7 @@ Bitnami charts can be used with [Kubeapps](https://kubeapps.com/) for deployment
 To install the chart with the release name `my-release`:
 
 ```bash
-$ helm install --name my-release stable/external-dns
+$ helm install my-release stable/external-dns
 ```
 
 The command deploys ExternalDNS on the Kubernetes cluster in the default configuration. The [Parameters](#parameters) section lists the parameters that can be configured during installation.
@@ -176,14 +176,14 @@ The following table lists the configurable parameters of the external-dns chart
 Specify each parameter using the `--set key=value[,key=value]` argument to `helm install`. For example,
 
 ```console
-$ helm install --name my-release \
+$ helm install my-release \
   --set provider=aws stable/external-dns
 ```
 
 Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,
 
 ```bash
-$ helm install --name my-release -f values.yaml stable/external-dns
+$ helm install my-release -f values.yaml stable/external-dns
 ```
 
 > **Tip**: You can use the default [values.yaml](values.yaml)
@@ -227,7 +227,7 @@ For instance, to install ExternalDNS on AWS, you need to:
 > Note: replace the placeholder HOSTED_ZONE_IDENTIFIER and HOSTED_ZONE_NAME, with your hosted zoned identifier and name, respectively.
 
 ```bash
-$ helm install --name my-release \
+$ helm install my-release \
   --set provider=aws \
   --set aws.zoneType=public \
   --set txtOwnerId=HOSTED_ZONE_IDENTIFIER \