ci: Fixes macos.yml
Stick to macos-11 to prevent accident broken always install meson with pip to prevent pull new version of python Cc: mesa-stable Signed-off-by:Yonggang Luo <luoyonggang@gmail.com> Acked-by:
Eric Engestrom <eric@igalia.com> Acked-by:
Dylan Baker <dylan.c.baker@intel.com> Part-of: <mesa/mesa!19640>