Check for X11-related 3rdparty updates for 5.9.7

5.9.7 is presumably in very strict mode by now, so only security issues or critical problems in the third party component warrant an update. Please review whether the following actually need updates; and update those that need it. (Presumably on 5.11, to cherry-pick back to 5.9.7, where possible.)

src/3rdparty/xcb/qt_attribution.json

• Upstream has had an update this year.

src/3rdparty/xkbcommon/qt_attribution.json

• 0.8.2 released this August; fixes some out-of-bounds access, so potentially security issues

src/3rdparty/pixman/qt_attribution.json

• Upstream is active.