Mark StartupProbe Feature gate beta v1.18

Signed-off-by: Mikkel Oscar Lyderik Larsen <[email protected]>

Author: mikkeloscar

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

@@ -134,7 +134,8 @@ different Kubernetes components.
 | `ServerSideApply` | `true` | Beta | 1.16 | |
 | `ServiceNodeExclusion` | `false` | Alpha | 1.8 | |
 | `ServiceTopology` | `false` | Alpha | 1.17 | |
-| `StartupProbe` | `false` | Alpha | 1.16 | |
+| `StartupProbe` | `false` | Alpha | 1.16 | 1.17 |
+| `StartupProbe` | `true` | Beta | 1.18 | |
 | `StorageVersionHash` | `false` | Alpha | 1.14 | 1.14 |
 | `StorageVersionHash` | `true` | Beta | 1.15 | |
 | `StreamingProxyRedirects` | `false` | Beta | 1.5 | 1.5 |