Update authentication.md

Author: shahincsejnu

content/en/docs/reference/access-authn-authz/authentication.md

@@ -206,7 +206,7 @@ spec:
 
 Service account bearer tokens are perfectly valid to use outside the cluster and
 
-can be used to create identities for long-standing jobs that wish to talk to the
+can be used to create identities for long standing jobs that wish to talk to the
 Kubernetes API. To manually create a service account, simply use the `kubectl
 
 create serviceaccount (NAME)` command. This creates a service account in the