build: add bootnode to Ubuntu PPAs too (#3766)

build/ci.go

@@ -83,6 +83,10 @@ var (
 			Name:        "geth",
 			Description: "Ethereum CLI client.",
 		},
+		{
+			Name:        "bootnode",
+			Description: "Ethereum bootnode.",
+		},
 		{
 			Name:        "rlpdump",
 			Description: "Developer utility tool that prints RLP structures.",