Dependencies field for all weight formats

[FynnBe]

No description provided.

[constantinpape]

Some minor comments.
But tests are still failing because something tries to cast string to int:

  bioimageio/spec/commands.py:111: in validate
      "warnings": ValidationWarning.get_warning_summary(validation_warnings),
  bioimageio/spec/shared/common.py:69: in get_warning_summary
      add_to_summary(summary, keys, msg)
  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
  
  s = {}, keys = [], msg = "missing 'pytorch_version'"
  
      def add_to_summary(s, keys, msg):
          key = keys.pop(0)
          if "[" in key:
              key, rest = key.split("[")
              assert rest[-1] == "]"
  >           idx = int(rest[:-1])
  E           ValueError: invalid literal for int() with base 10: 'torchscript'
  
  bioimageio/spec/shared/common.py:38: ValueError

[constantinpape]

@FynnBe the tests pass now, could you still address the 2 comments?

[constantinpape]

I left one suggestion to reformulate the doc string. Otherwise this looks good to me, feel free to merge when you think this is ready @FynnBe