We now build against a specific Windows SDK rather than whatever happens
to be installed on the host machine.
This also rolls the buildroot to include change
https://github.com/flutter/buildroot/pull/448, which generates the WinRT
headers from the CIPD Windows SDK.
This also rolls an updated version of cppwinrt that includes supports
for long paths.
This also re-enables the UWP builder.
Builders are read from a json file to get their last builds using
buildbucket and calculate the tree status. Some builders were not being
used for the tree status validation allowing rollers to land changes
even though some builders were failing.
Bug:
https://github.com/flutter/flutter/issues/64061
* add supported luci builders
* fix license
* add readme
* add code to validate json contents
* license
* move dev to ci
* fix license
* add shell script to run test
