Failed to build with Meson 0.42.1

Not sure if the problem is with the old version of Meson or not.

$meson build
The Meson build system
Version: 0.42.1
Source dir: /usr/local/google/home/tfoucu/third_party/dav1d
Build dir: /usr/local/google/home/tfoucu/third_party/dav1d/build
Build type: native build

Meson encountered an error in file meson.build, line 63, column 45:
Expecting rbracket got id.
            ['_WIN32_WINNT',                0x0601],
            ^________________________________^

Looks like the meson build is using feature coming from 0.45 and up. Maybe update the documentation about the Meson build version to use.