Resolve FFI warnings from bundled tooling

[tas50]

FFI 1.12 introduced warnings if you try to override a struct layout, which we are apparently doing. I'm pinning to < 1.12, but we need 1.12 for Ruby 2.7 support. This needs to get fixed in our deps.

It produces output similar to this (this is actually from DK, but it's the same)

C:/opscode/chefdk/embedded/lib/ruby/gems/2.6.0/gems/ffi-1.12.1-x64-mingw32/lib/ffi/struct.rb:207:in `layout': [DEPRECATION] Struct layout is already defined for class Windows::ServiceStructs::SERVICE_STATUS_PROCESS. Redefinition as in C:/opscode/chefdk/embedded/lib/ruby/gems/2.6.0/gems/win32-service-2.1.4/lib/win32/windows/structs.rb:72:in `<class:SERVICE_STATUS_PROCESS>' will be disallowed in ffi-2.0. (StructuredWarnings::StandardWarning)

Chef Workstation Version

latest

Platform Version

Windows

[tas50]

This is fixed with #914