Bump shelf to 0371a64bd3b99044ee3158bacf8813bba735a9c7
Bump shelf to 0371a64bd3b99044ee3158bacf8813bba735a9c7

Changes:
```
> git log --format="%C(auto) %h %s" 9dab944..0371a64
 https://dart.googlesource.com/shelf.git/+/0371a64 Changed advertised server technology response header (#258)

```

Diff: https://dart.googlesource.com/shelf.git/+/9dab94469d50e89a6e4e2c0086b717bddb0bf78a~..0371a64bd3b99044ee3158bacf8813bba735a9c7/
Change-Id: I1ac864de24f5395e74816952618bcfd58d9f5d13
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/252800
Auto-Submit: Kevin Moore <1d6e7d10d051cf619c5282da3c28fd8d3e0a65a4@google.com>
Reviewed-by: Devon Carew <e996497f4f2225f0ee7a9f4d1696ee710b488b66@google.com>
Commit-Queue: Devon Carew <e996497f4f2225f0ee7a9f4d1696ee710b488b66@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk