Use SecureRandom instead of Random (#15459)

Make sure that SecureRadom is used whenever the random number
is used for cryptographic operations, e.g. as nonce/salt.

Signed-off-by: Holger Friedrich <mail@holger-friedrich.de>

bundles/org.openhab.binding.miio/src/main/java/org/openhab/binding/miio/internal/cloud/CloudUtil.java

@@ -24,6 +24,7 @@ import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.security.SecureRandom;
 import java.util.ArrayList;
 import java.util.Base64;
 import java.util.List;
@@ -45,7 +46,7 @@ import org.slf4j.Logger;
 @NonNullByDefault
 public class CloudUtil {
 
-    private static final Random RANDOM = new Random();
+    private static final Random RANDOM = new SecureRandom();
 
     /**
      * Saves the Xiaomi cloud device info with tokens to file