I've targeted 4.6.x because the template added to ServiceGridFSRepository.

The ignored errors are because

• a while(true) in Command/TailCursorDoctrineODMCommand.php which psalm thinks that the return type must be never.
  - In ContainerRepositoryFactory, there is a $customRepositoryName variable that with type class-string|null and when doing if (! class_exists($customRepositoryName)) after if ($customRepositoryName !== null), psalm says All possible types for this argument were invalidated.
• psalm/symfony-plugin added generics to AbstractType which seems not accurate, so we better don't use them.

psalm/symfony-plugin 5 requires php 7.4, so we need #763 or remove this dependency if it's not really useful (it will if we pass a path to the compiled container in XML).