Update deny.toml - allow Unicode-3.0 license (#89)

The unicode.org FAQ describes it as a "permissive MIT type of license" and it
is OSI approved. We need this because several new dependencies with this
license are now being pulled in by the url crate (through idna).

deny.toml

@@ -24,6 +24,7 @@ allow = [
     "MIT",
     "MPL-2.0",
     "OpenSSL",
+    "Unicode-3.0",
     "Unicode-DFS-2016",
 ]
 deny = []