feat(spanner): bump to v1.5.24

This change will introduce a new behavior where transactions will be
retried more often. This change will very likely reveal bugs where
resources, which are pointers, are mutated within the transaction in
such a way that these mutations persists at the beginning of a retried
transaction. Beware!

tools/sgcloudspanner/emulator.go

@@ -17,7 +17,7 @@ import (
 // https://console.cloud.google.com/gcr/images/cloud-spanner-emulator/global/emulator
 const (
 	url     = "gcr.io/cloud-spanner-emulator/emulator"
-	version = "1.5.22"
+	version = "1.5.24"
 	image   = url + ":" + version
 )