crosvm: update homepage

There's now a website in addition to the repo, so we should use that.

pkgs/applications/virtualization/crosvm/default.nix

···
 
   meta = with lib; {
     description = "A secure virtual machine monitor for KVM";
-    homepage = "https://chromium.googlesource.com/crosvm/crosvm/";
+    homepage = "https://crosvm.dev/";
     mainProgram = "crosvm";
     maintainers = with maintainers; [ qyliss ];
     license = licenses.bsd3;