[pkg/js] Update pubspec to 3.7.

No reformatting required.

Change-Id: I23ff15d0ef5b2e97544332aebd9934970a7332f0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/400721
Commit-Queue: Mayank Patke <[email protected]>
Auto-Submit: Mayank Patke <[email protected]>
Reviewed-by: Nate Biggs <[email protected]>
Commit-Queue: Nate Biggs <[email protected]>

Author: fishythefish

pkg/js/pubspec.yaml

@@ -12,7 +12,7 @@ topics:
  - interop
 
 environment:
-  sdk: ^3.1.0
+  sdk: ^3.7.0-0
 
 # We use 'any' version constraints here as we get our package versions from
 # the dart-lang/sdk repo's DEPS file. Note that this is a special case; the