node: update KEP 2625 to the latest template

cosmetic changes, no changes in content besides the bare minimum
neededl to adjust to the new template.

Signed-off-by: Francesco Romani <[email protected]>

Author: ffromani

keps/prod-readiness/sig-node/2625.yaml

@@ -3,3 +3,5 @@ alpha:
   approver: "@johnbelamaric"
 beta:
   approver: "@johnbelamaric"
+stable:
+  approver: "@johnbelamaric"