Bump vm_service from 14.3.1 to 15.0.0 (grpc#751)

Bumps [vm_service](https://github.com/dart-lang/sdk/tree/main/pkg) from 14.3.1 to 15.0.0.
- [Changelog](https://github.com/dart-lang/sdk/blob/main/CHANGELOG.md)
- [Commits](https://github.com/dart-lang/sdk/commits/HEAD/pkg)

---
updated-dependencies:
- dependency-name: vm_service
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Moritz <mosum@google.com>

pubspec.yaml

@@ -27,7 +27,7 @@ dev_dependencies:
   test: ^1.16.0
   stream_channel: ^2.1.0
   stream_transform: ^2.0.0
-  vm_service: ">=11.6.0 <15.0.0"
+  vm_service: ">=11.6.0 <16.0.0"
   fake_async: ^1.3.1
 
 false_secrets: