Sure, it's not official, but it's pretty obvious I think: Edge is moving to Chromium. I'm sure Chakra will continue to be bundled with Windows somehow, eg in IE and whatnot, but if you look at Chakra's recent release history in GitHub, it's all security patches.
And it makes sense, why would MS invest in a JS engine it's not planning to use?
And it makes sense, why would MS invest in a JS engine it's not planning to use?