release: update predecessor map for 22.2.13

Release note: None
Epic: None

Author: Thomas Hardy

pkg/testutils/release/cockroach_releases.yaml

@@ -8,7 +8,7 @@
   - 22.1.19
   predecessor: "21.2"
 "22.2":
-  latest: 22.2.12
+  latest: 22.2.13
   withdrawn:
   - 22.2.4
   - 22.2.8