Remove duplicate word in initial design documentation

**What happened:** This is to remove duplicate word in the initial design documentation - https://github.com/fidelity/kconnect/blob/main/docs/proposals/20200607-initial-design.md **What did you expect to happen:** Remove duplicate 'get get' > There doesn't exist a good open source solution that based on your user credentials (i.e. SAML, OAuth2/OIDC, IAM) will discover what Kuberneres clusters you have access to and how to get get the kubeconfig file for a cluster you have access to.