Update Kubelet RotateKubeletClientCertificate feature since v1.8 (#1…

…3070)

* Update feature-gates.md

Update PodPriority feature to beta since v1.11

* Update Kubelet RotateKubeletClientCertificate feature since v1.8
* fix feature-gates.md and kubelet-tls-bootstrapping.md Kubelet RotateKubeletClientCertificate feature since v1.8

content/en/docs/reference/command-line-tools-reference/feature-gates.md

@@ -124,7 +124,7 @@ different Kubernetes components.
 | `ResourceLimitsPriorityFunction` | `false` | Alpha | 1.9 | |
 | `ResourceQuotaScopeSelectors` | `false` | Alpha | 1.11 | 1.11 |
 | `ResourceQuotaScopeSelectors` | `true` | Beta | 1.12 | |
-| `RotateKubeletClientCertificate` | `true` | Beta | 1.7 | |
+| `RotateKubeletClientCertificate` | `true` | Beta | 1.8 | |
 | `RotateKubeletServerCertificate` | `false` | Alpha | 1.7 | 1.11 |
 | `RotateKubeletServerCertificate` | `true` | Beta | 1.12 | |
 | `RunAsGroup` | `true` | Beta | 1.14 | |

content/en/docs/reference/command-line-tools-reference/kubelet-tls-bootstrapping.md

@@ -416,7 +416,7 @@ be used as serving certificates, or `server auth`.
 However, you _can_ enable its server certificate, at least partially, via certificate rotation.
 
 ### Certificate Rotation
-Kubernetes v1.7 and higher kubelet implements __beta__ features for enabling
+Kubernetes v1.8 and higher kubelet implements __beta__ features for enabling
 rotation of its client and/or serving certficates.  These can be enabled through
 the respective `RotateKubeletClientCertificate` and
 `RotateKubeletServerCertificate` feature flags on the kubelet and are enabled by