Revert "Revert "Update cobra/pflag. Also update generated kubectl documentation.""

This reverts commit 69432e8b2f.

    COMMIT_BLOCKED_ON_GENDOCS

docs/kubectl-clusterinfo.md

@@ -11,6 +11,12 @@ Display addresses of the master and services with label kubernetes.io/cluster-se
 kubectl clusterinfo
 ```
 
+### Options
+
+```
+  -h, --help=false: help for clusterinfo
+```
+
 ### Options inherrited from parent commands
 
 ```
@@ -22,7 +28,6 @@ kubectl clusterinfo
       --client-key="": Path to a client key file for TLS.
       --cluster="": The name of the kubeconfig cluster to use
       --context="": The name of the kubeconfig context to use
-  -h, --help=false: help for kubectl
       --insecure-skip-tls-verify=false: If true, the server's certificate will not be checked for validity. This will make your HTTPS connections insecure.
       --kubeconfig="": Path to the kubeconfig file to use for CLI requests.
       --log_backtrace_at=:0: when logging hits line file:N, emit a stack trace