ChangeLog.d/fix-possible-false-success-in-mbedtls_cipher_check_tag.txt

Changes
   * Calling AEAD tag-specific functions for non-AEAD algorithms (which
     should not be done - they are documented for use only by AES-GCM and
     ChaCha20+Poly1305) now returns MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE
     instead of success (0).