fix: report invalid public key to logger

update.go

@@ -99,8 +99,9 @@ func fetchFile(file string) ([]byte, error) {
 
 func publickey() []byte {
 	pub, err := base64.StdEncoding.DecodeString(publicKeyString)
-	if err != nil {
+	if err != nil { // Should only happen when distributor ships an invalid public key
-		panic(err) // it's hardcoded, we should never hit this, panic if we do
+                log.Fatalf("Error while reading public key: %s\nContact the distribution '%s' about this error.\n", err, distribution)
+                os.Exit(1)
 	}
 	return pub
 }