Bump pub to f6457fd20c9a9734a747262b1bcc2200c8357efb

Changes:
```
> git log --format="%C(auto) %h %s" 06dda29..f6457fd
 https://dart.googlesource.com/pub.git/+/f6457fd2 Add customizable `category` to pub `Command` (4611)
 https://dart.googlesource.com/pub.git/+/81409a1c Bump dart_flutter_team_lints from 3.5.1 to 3.5.2 (4608)

```

Diff: https://dart.googlesource.com/pub.git/+/06dda296bfbdb345ecf696fc88b28ec6c02c5d7b..f6457fd20c9a9734a747262b1bcc2200c8357efb/
Change-Id: I896b2176f0ad4b63e286225d93f06a9fa88b5e69
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/436320
Reviewed-by: Sigurd Meldgaard <[email protected]>
Commit-Queue: Daco Harkes <[email protected]>

Author: dcharkes

DEPS

@@ -142,7 +142,7 @@ vars = {
   "material_color_utilities_rev": "799b6ba2f3f1c28c67cc7e0b4f18e0c7d7f3c03e",
   "native_rev": "7944c5a0d26f3948273096239c9c2a8d6f0cda54", # rolled manually while native assets are experimental
   "protobuf_rev": "0bfff0ca150959c92dac525474d73bde946f3391",
-  "pub_rev": "06dda296bfbdb345ecf696fc88b28ec6c02c5d7b", # rolled manually
+  "pub_rev": "f6457fd20c9a9734a747262b1bcc2200c8357efb", # rolled manually
   "shelf_rev": "082d3ac2d13a98700d8148e8fad8f3e12a6fd0e1",
   "sync_http_rev": "dc54465f07d9652875deeade643256dafa2fbc6c",
   "tar_rev": "5a1ea943e70cdf3fa5e1102cdbb9418bd9b4b81a",