Add a --context option

Signed-off-by: Sylvain Rabot <sylvain@abstraction.fr>

docs/cmd/flux_create.md

@@ -18,6 +18,7 @@ The create sub-commands generate sources and resources.
 ### Options inherited from parent commands
 
 ```
+      --context string      kubernetes context to use
       --kubeconfig string   path to the kubeconfig file (default "~/.kube/config")
   -n, --namespace string    the namespace scope for this operation (default "flux-system")
       --timeout duration    timeout for this operation (default 5m0s)