Update required go version

Today we have k8s upstream training in Japan, and we found this table
is not updated at this time.
This does it.

Author: oomichi

contributors/devel/development.md

@@ -285,7 +285,8 @@ different versions of Kubernetes.
 | 1.19 - 1.20    | 1.15.5      |
 | 1.21 - 1.22    | 1.16.7      |
 | 1.23           | 1.17        |
-| 1.24+          | 1.18        |
+| 1.24           | 1.18        |
+| 1.25+          | 1.19        |
 
 ##### A Note on Changing Go Versions