Merge pull request #1 from offsoc/alert-autofix-9

Fix code scanning alert no. 9: Implicit narrowing conversion in compound assignment

service/src/test/java/org/whispersystems/textsecuregcm/backup/BackupManagerTest.java

@@ -383,7 +383,7 @@ public void signatureValidation() throws VerificationFailedException {
 
     // an invalid signature
     final byte[] wrongSignature = Arrays.copyOf(signature, signature.length);
-    wrongSignature[1] += 1;
+    wrongSignature[1] = (byte) (wrongSignature[1] + 1);
 
     // shouldn't be able to set a public key with an invalid signature
     assertThatExceptionOfType(StatusRuntimeException.class)