Update quickstart example to work with current kubernetes versions

[manuschillerdev]

Describe the bug
https://github.com/buzzfeed/sso/blob/master/quickstart/ in combination with https://medium.com/@while1eq1/single-sign-on-for-internal-apps-in-kubernetes-using-google-oauth-sso-2386a34bc433 is a really cool documentation on how to get started with buzzfeed/sso on kubernetes. The examples however are outdated for current kubernetes versions.

For example: (see next section)

To Reproduce
the first step would be to apply the config from:
https://github.com/buzzfeed/sso/blob/master/quickstart/kubernetes/sso-auth-deployment.yml
result

kubectl apply -f sso-auth-deployment.yml results in

error: unable to recognize "sso-auth-deployment.yml": no matches for kind "Deployment" in version "extensions/v1beta1"

Expected behavior
The configs are compatible with current kubernetes / kubectl versions.

Desktop (please complete the following information):

• OS: Mac Catalina latest
• kubectl:
  Client Version: v1.18.2
  Server Version: v1.17.5

It would be really cool if the example could be fixed for current versions! :)

[2o1o0]

Hello!

Maybe I'm a bit late to this party, but anyway...

This PR should help.