windows/meson cfbot warnings

Since a few days ago, the windows/meson task has been spewing messages for each tap
test:

| Unknown TAP version. The first line MUST be `TAP version <int>`. Assuming version 12.

I guess because the image is updated to use meson v1.0.0.
https://github.com/mesonbuild/meson/commit/b7a5c384a1f1ba80c09904e7ef4f5160bdae3345

mesonbuild/mtest.py-        if version is None:
mesonbuild/mtest.py:            self.warnings.append('Unknown TAP version. The first line MUST be `TAP version <int>`.
Assumingversion 12.')
 
mesonbuild/mtest.py-            version = 12

-- 
Justin