Revert "Bump pub to d69493e5163553bde53c0889b7479dee02f550bf"

This reverts commit a06ade1d14.

Reason for revert: Broke flutter: https://ci.chromium.org/ui/p/dart/builders/ci.sandbox/flutter-engine-linux/19264/overview

Original change's description:
> Bump pub to d69493e5163553bde53c0889b7479dee02f550bf
>
> Changes:
> ```
> > git log --format="%C(auto) %h %s" 048e3ad..d69493e
>  https://dart.googlesource.com/pub.git/+/d69493e5 Don't allow non-null-safety constraints in the root pubspec (3800)
>  https://dart.googlesource.com/pub.git/+/3514d7e7 Fail gracefully when tar file contains duplicate entries (3805)
>  https://dart.googlesource.com/pub.git/+/0b3b8b44 Give full error even in summary mode (3804)
>  https://dart.googlesource.com/pub.git/+/09c29722 Allow adding and removing dependency overrides (3716)
>  https://dart.googlesource.com/pub.git/+/7184d1b5 accept 'topics' property in pubspec.yaml (3796)
>  https://dart.googlesource.com/pub.git/+/cd106dfd Improve usage text of get (3792)
>  https://dart.googlesource.com/pub.git/+/019d61cb Handle bad git revisions (3791)
>  https://dart.googlesource.com/pub.git/+/e3ff7a99 Use 'pkg' and 'packages' to trigger suggestions for the pub command (3731)
>  https://dart.googlesource.com/pub.git/+/ea24bf22 Better error when path dependency has no pubspec.yaml (3787)
>  https://dart.googlesource.com/pub.git/+/da2a0144 Drop --use-data-isolate-strategy flag for tests (3788)
>  https://dart.googlesource.com/pub.git/+/a565858e Improve documentation of `pub token` and subcommands (3778)
>  https://dart.googlesource.com/pub.git/+/dd320459 Add test for publishing and consuming files with unicode characters in name (3785)
>  https://dart.googlesource.com/pub.git/+/c4226d9f Fail tests on errors thrown by test PackageServer (3784)
>  https://dart.googlesource.com/pub.git/+/12019939 Consider pubspec_overrides.yaml when publishing (3782)
>  https://dart.googlesource.com/pub.git/+/d8a97497 Allow addition of tokens for insecure localhost repositories (3777)
>
> ```
>
> Diff: https://dart.googlesource.com/pub.git/+/048e3ad2b5e1b4ebe6883addbc95722be6904a7b..d69493e5163553bde53c0889b7479dee02f550bf/
> Change-Id: I92af981e9cb6aaedfcd75a7327dfef071645306b
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/285908
> Reviewed-by: Jonas Jensen <jonasfj@google.com>
> Commit-Queue: Sigurd Meldgaard <sigurdm@google.com>
> Reviewed-by: William Hesse <whesse@google.com>

Change-Id: I0cb55a2cf4602868649c153dd1d86ba91c751ce5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/288200
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Alexander Thomas <athom@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>
Auto-Submit: Sigurd Meldgaard <sigurdm@google.com>

DEPS

@@ -156,7 +156,7 @@ vars = {
   "path_rev": "24b58a2499440cc3d12d2b3c2f52b95f91ff1c0a",
   "pool_rev": "694cfd867d8d84857fc42a8d07933013f0d25305",
   "protobuf_rev": "75bc380a6e9601565606a13dee16c5ab2bf5019c",
-  "pub_rev": "d69493e5163553bde53c0889b7479dee02f550bf", # disable rev_sdk_deps.dart
+  "pub_rev": "048e3ad2b5e1b4ebe6883addbc95722be6904a7b", # disable rev_sdk_deps.dart
   "pub_semver_rev": "c0e6ea74ccfbfdb2ef54c7cd9ad31455ca8e481f",
   "shelf_rev": "e3cfe796ad478cb4b61ad8e68ea29644c0bb1037",
   "source_map_stack_trace_rev": "45ea3688b6bec1eb565c38c4e28f37b01f8a0fa9",

tools/bots/pub_integration_test.py

@@ -12,7 +12,7 @@ import tempfile
 
 PUBSPEC = """name: pub_integration_test
 environment:
-  sdk: '^2.19.0'
+  sdk: '>=2.10.0 <=3.0.0'
 dependencies:
   shelf:
   test: