Remove helm3 flag where not required

The flag was removed.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Author: alexellis

_posts/2020-01-30-get-started-with-java-openjdk11.md

@@ -43,8 +43,7 @@ curl -sSLf https://dl.get-arkade.dev | sudo sh
 Now install openfaas:
 
 ```sh
-arkade install openfaas \
-  --helm3
+arkade install openfaas
 ```
 
 You can also customise values from the helm chart's README by passing in `--set`, for instance, or by using a user-friendly flag shown below:
@@ -64,7 +63,6 @@ Flags:
       --direct-functions              Invoke functions directly from the gateway (default true)
       --function-pull-policy string   Pull policy for functions (default "Always")
       --gateways int                  Replicas of gateway (default 1)
-      --helm3                         Use helm3 instead of the default helm2
   -h, --help                          help for openfaas
   -l, --load-balancer                 Add a loadbalancer
   -n, --namespace string              The namespace for the core services (default "openfaas")

_posts/2020-02-12-get-started-with-python-mongo.md

@@ -42,8 +42,7 @@ curl -sSLf https://dl.get-arkade.dev | sudo sh
 Now install openfaas:
 
 ```sh
-arkade install openfaas \
-  --helm3
+arkade install openfaas
 ```
 
 You can also customise values from the helm chart's README by passing in `--set`, for instance, or by using a user-friendly flag shown below:
@@ -63,7 +62,6 @@ Flags:
       --direct-functions              Invoke functions directly from the gateway (default true)
       --function-pull-policy string   Pull policy for functions (default "Always")
       --gateways int                  Replicas of gateway (default 1)
-      --helm3                         Use helm3 instead of the default helm2
   -h, --help                          help for openfaas
   -l, --load-balancer                 Add a loadbalancer
   -n, --namespace string              The namespace for the core services (default "openfaas")

_posts/2020-08-28-openfaas-arkade.md

@@ -91,7 +91,6 @@ Flags:
       --direct-functions              Invoke functions directly from the gateway (default true)
       --function-pull-policy string   Pull policy for functions (default "Always")
       --gateways int                  Replicas of gateway (default 1)
-      --helm3                         Use helm3, if set to false uses helm2 (default true)
   -h, --help                          help for openfaas
       --ingress-operator              Get custom domains and Ingress records via the ingress-operator component
   -l, --load-balancer                 Add a loadbalancer

_posts/2020-3-29-managed-services-serverless.md

@@ -48,7 +48,7 @@ Now that we have an idea of the value that Crossplane provides when used alongsi
 We [started](https://youtu.be/XphQgB87U-s?t=1521) the demo by installing Crossplane with [arkade](https://github.com/alexellis/arkade), the simplest way to get Crossplane up and running in your Kubernetes cluster.
 
 ```console
-arkade install crossplane --helm3
+arkade install crossplane
 ```
 
 We followed up by installing the Crossplane [AWS Provider](https://github.com/crossplane/provider-aws) and supplying credentials for Crossplane to communicate with the AWS API. You can find documentation on how to do this for your cloud provider of choice in the Crossplane [documentation](https://crossplane.io/docs/v0.9/configure.html). After that, we created an AWS `S3BucketClass` resource in our cluster. This is a custom resource type that Crossplane provides to allow an infrastructure administrator to define configuration for an [Amazon S3 bucket](https://aws.amazon.com/s3/) that is available for use by developers. This class exposes the same fields that you would find in the AWS console, or when using any infrastructure as code tool. Our configuration for this demo looks as follows: