validate: yamllint: ignore "truthy value should be one of" warnings
validate: yamllint: ignore "truthy value should be one of" warnings

Suppresses warnings like:

    LANG=C.UTF-8 yamllint -c hack/validate/yamllint.yaml -f parsable .github/workflows/*.yml
    .github/workflows/ci.yml:7:1: [warning] truthy value should be one of [false, true] (truthy)
    .github/workflows/windows.yml:7:1: [warning] truthy value should be one of [false, true] (truthy)

Signed-off-by: Sebastiaan van Stijn <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@gone.nl>

jimjag/docker,konstruktoid/docker-upstream,konstruktoid/docker-upstream,jimjag/docker,konstruktoid/docker-upstream,moul/docker,thaJeztah/docker,trebonian/docker,konstruktoid/docker-upstream,trebonian/docker,moul/docker,mahak/docker,Mokolea/docker,jimjag/docker,moby/moby,mahak/docker,cpuguy83/docker,cpuguy83/docker,mahak/docker,trebonian/docker,mahak/docker,thaJeztah/docker,Mokolea/docker,Ramzec/docker,Ramzec/docker,thaJeztah/docker,moby/moby,Mokolea/docker,trebonian/docker,thaJeztah/docker,Ramzec/docker,Mokolea/docker,cpuguy83/docker,moul/docker,cpuguy83/docker,moul/docker,jimjag/docker,moby/moby,moby/moby,Ramzec/docker