Backport PR matplotlib#17552: ci: Add xcb libraries that were removed from PyQt5.

Author: tacaswell

.travis.yml

@@ -36,6 +36,13 @@ addons:
       - libgeos-dev
       - libgirepository1.0-dev
       - libsdl2-2.0-0
+      - libxkbcommon-x11-0
+      - libxcb-icccm4
+      - libxcb-image0
+      - libxcb-keysyms1
+      - libxcb-randr0
+      - libxcb-render-util0
+      - libxcb-xinerama0
       - lmodern
       - fonts-freefont-otf
       - texlive-pictures