package/webkitgtk: security bump to version 2.24.4

package/webkitgtk: security bump to version 2.24.4

This is a minor release which includes fixes for CVE-2019-8644,
CVE-2019-8649, CVE-2019-8658, CVE-2019-8669, CVE-2019-8676,
CVE-2019-8678, CVE-2019-8680, CVE-2019-8683, CVE-2019-8684, and
CVE-2019-8688.

This release also contains many build fixes, a few media playback
improvements, and a Web compatibility fix. For a complete list,
the full release notes at:

  https://webkitgtk.org/2019/08/28/webkitgtk2.24.4-released.html

The detailed security advisory can be found at:

  https://webkitgtk.org/security/WSA-2019-0004.html

Signed-off-by: Adrian Perez de Castro <aperez@igalia.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>