ci/msys2: switch to Python 3.11 to fix crashes during build

There is a long-standing bug with random crashes of Python 3.10 on CI.

See:
https://github.com/python/cpython/issues/105400
https://github.com/msys2/MINGW-packages/issues/11864
https://github.com/msys2/MINGW-packages/issues/17415

.github/workflows/build.yml

@@ -271,7 +271,7 @@ jobs:
             meson:p
             ninja:p
             pkgconf:p
-            python:p
+            python3.11:p
             rst2pdf:p
             rubberband:p
             shaderc:p