Update helm install for helm 3

--name isn't allowed in helm 3 as name is now required.

Author: jabbera

doc/zero-to-binderhub/setup-binderhub.rst

@@ -310,7 +310,7 @@ First, get the latest helm chart for BinderHub.::
 Next, **install the Helm Chart** using the configuration files
 that you've just created. Do this by running the following command::
 
-    helm install jupyterhub/binderhub --version=0.2.0-3b53fce  --name=<choose-name> --namespace=<choose-namespace> -f secret.yaml -f config.yaml
+    helm install <choose-name> jupyterhub/binderhub --version=0.2.0-3b53fce --namespace=<choose-namespace> -f secret.yaml -f config.yaml
 
 This command will install the Helm chart released on March 3rd, 2019 as
 identified by the commit hash (the random string after `0.2.0-`), which is