Add security severity

Author: joefarebrother

java/ql/src/Security/CWE/CWE-524/SensitiveKeyboardCache.ql

@@ -3,6 +3,7 @@
  * @description Sensitive information should not be saved to the keyboard cache.
  * @kind problem
  * @problem.severity warning
+ * @security-severity 8.1
  * @id java/android/sensitive-keyboard-cache
  * @tags security
  *       external/cwe/cwe-524