message: udpate license
diff: @@ -3,7 +3,7 @@ name = "salsa"
  version = "0.2.0"
  authors = ["Niko Matsakis <niko@alum.mit.edu>"]
  edition = "2018"
  -license = "Apache-2.0/MIT"
  +license = "Apache-2.0 OR MIT"
  repository = "https://github.com/nikomatsakis/salsa"
  description = "A generic framework for on-demand, incrementalized computation (experimental)"
  readme = "README.md"
  