Replace license without console access.

If you need to update your license without access to the console:

`kubectl get secret tectonic-license-secret -n tectonic-system -o yaml > tectonic-license-secret.yaml`

Pull down your new license from account.coreos.com, and save it as license.txt

`base64 license.txt > license64.txt`

Now edit the license secret and replace the value for the `license:` key with the base64 of the new license from license64.txt.

Finally, replace the original license secret with the new one:

`kubectl replace -f tectonic-license-secret.yaml -n tectonic-system`