cloud: fix %v in cases where we should use %w

Change-Id: I161fe87fbc2bf8c4c2c7756074fc1050f268121e
Reviewed-on: https://review.monogon.dev/c/monogon/+/3099
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/cloud/agent/takeover/takeover.go b/cloud/agent/takeover/takeover.go
index 094c688..645b27e 100644
--- a/cloud/agent/takeover/takeover.go
+++ b/cloud/agent/takeover/takeover.go
@@ -120,7 +120,7 @@
 	}
 	agentInitRaw, err := proto.Marshal(&agentInit)
 	if err != nil {
-		return nil, fmt.Errorf("unable to marshal AgentInit message: %v", err)
+		return nil, fmt.Errorf("unable to marshal AgentInit message: %w", err)
 	}
 
 	// Append AgentInit spec to initramfs