productbuild: escape pkg-ref urls

Inspired-by: James Goruk <james.goruk@gmail.com>
Fixes: #18645

Source/CPack/cmCPackPKGGenerator.cxx

@@ -225,7 +225,8 @@ void cmCPackPKGGenerator::CreateChoice(const cmCPackComponent& component,
     xout.Content(this->GetPackageName(component));
   } else {
     xout.Content("file:./");
-    xout.Content(relativePackageLocation);
+    xout.Content(cmSystemTools::EncodeURL(relativePackageLocation,
+                                          /*escapeSlashes=*/false));
   }
   xout.EndElement(); // pkg-ref
 }