macOS: change notarization password key

Kde application password key is stored as AC_PASSWORD
instead of KRITA_AC_PASS. To transfer old keyname to
the new key:

xcrun altool --store-password-in-keychain-item "AC_PASSWORD" -u "AC_USERNAME" -p "$(security find-generic-password -l "KRITA_AC_PASS" -w)"

where AC_USERNAME is the appleID email/username