fix(package): create symlink to expose binary as "zen"

This change might fix the issue mentioned here:
https://github.com/0xc000022070/zen-browser-flake/issues/36

But the problem with this is that if both zen flavors are installed
then one of them will have more priority than the other so they should
use complete binary name like "zen-twilight" or "zen-beta" instead of
only "zen"

package.nix

@@ -83,6 +83,8 @@ in
 
       mkdir -p "$out/bin"
       ln -s "$prefix/lib/zen-bin-${variant.version}/zen" "$out/bin/${binaryName}"
+      # ! twilight and beta could collide if both are installed
+      ln -s "$prefix/lib/zen-bin-${variant.version}/zen" "$out/bin/zen"
 
       mkdir -p "$out/lib/zen-${variant.version}/distribution"
       ln -s ${policiesJson} "$out/lib/zen-${variant.version}/distribution/policies.json"