Add stable chart repo link to README

[gyliu513]

Is this a request for help?:

---

Is this a BUG REPORT or FEATURE REQUEST? (choose one):

Version of Helm and Kubernetes:

Which chart:

What happened:

How do I enable the Incubator repository?

To add the Incubator charts for your local client, run helm repo add:

$ helm repo add incubator https://kubernetes-charts-incubator.storage.googleapis.com/
"incubator" has been added to your repositories

You can then run helm search incubator to see the charts.

We should have a section telling customer how to add the stable repo.

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know:

[gyliu513]

/assign @gyliu513

[unguiculus]

The stable repo is added automatically. You just do helm init and are good to go.

[Ciantic]

Except when it doesn't? Helm 3.

$ helm init
...prints just help...
$ helm repo update
Error: no repositories found. You must add one before updating

Edit found it:

helm repo add stable https://kubernetes-charts.storage.googleapis.com

(This is literally second time I look it up this week, because everyone is transitioning to helm3)

[pre]

helm init ought to be enough for anybody 🙄

[morganlaneap]

helm init was removed wasn't it? I feel like @Ciantic has a point with helm repo add stable https://kubernetes-charts.storage.googleapis.com

[scones]

helm init was removed wasn't it? I feel like @Ciantic has a point with helm repo add stable https://kubernetes-charts.storage.googleapis.com

solves Error: no repositories found. You must add one before updating after fresh helm 3 install on helm repo update