helm docs update.

docs/helm/helm_fetch.md

@@ -33,10 +33,12 @@ helm fetch [flags] [chart URL | repo/chartname] [...]
       --devel                use development versions, too. Equivalent to version '>0.0.0-0'. If --version is set, this is ignored.
       --key-file string      identify HTTPS client using this SSL key file
       --keyring string       keyring containing public keys (default "~/.gnupg/pubring.gpg")
+      --password string      chart repository password
       --prov                 fetch the provenance file, but don't perform verification
       --repo string          chart repository url where to locate the requested chart
       --untar                if set to true, will untar the chart after downloading it
       --untardir string      if untar is specified, this flag specifies the name of the directory into which the chart is expanded (default ".")
+      --username string      chart repository username
       --verify               verify the package against its signature
       --version string       specific version of a chart. Without this, the latest version is fetched
 ```