Add explicit defaulted copy ctor to `Values` (#1176)
Add explicit defaulted copy ctor to `Values` (#1176)

Summary:
X-link: https://github.com/facebook/yoga/pull/1176

`Values` is a wrapper to story an array of YGValue's as CompactValues.

From https://github.com/facebook/yoga/issues/1174 we see a warning `Wdeprecated-copy` beacuse a user-defined copy constructor is not present, but a user-defined asignment operator is (the defaulted one). This adds an explicitly defaulted copy contructor which should silence the warning I think.

Changelog:
[Internal]

Reviewed By: christophpurrer

Differential Revision: D41447490

fbshipit-source-id: 8cc8f291cf12014d87cc71c4598bb84fdd6cd930

facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho,facebook/litho