Fix code scanning alert no. 4: Use of a broken or risky cryptographic…

… algorithm

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

src/main/java/cc/baka9/catseedlogin/util/CommunicationAuth.java

@@ -9,7 +9,7 @@ public class CommunicationAuth {
 
     static {
         try {
-            messageDigest = MessageDigest.getInstance("MD5");
+            messageDigest = MessageDigest.getInstance("SHA-256");
         } catch (NoSuchAlgorithmException e) {
             throw new RuntimeException(e);
         }