via: fix license metadata

The via electron wrapper claims to be gpl, however source code is not
available and never became available despite frequent requests over a
substantial time period.

This change fixes its metadata in nixpkgs to avoid misleading users.

pkgs/by-name/vi/via/package.nix

@@ -36,7 +36,8 @@ appimageTools.wrapType2 {
   meta = with lib; {
     description = "Yet another keyboard configurator";
     homepage = "https://caniusevia.com/";
-    license = licenses.gpl3;
+    # Upstream claims to be GPL-3 but doesn't release source code
+    license = licenses.unfreeRedistributable;
     maintainers = with maintainers; [ emilytrau ];
     platforms = [ "x86_64-linux" ];
     mainProgram = "via";