WP-4759 Add explicit dependency on meta

[evanweible-wf]

Issue

pub publish --dry-run shows this warning:

* line 17, column 1 of lib/src/web_socket/global_web_socket_monitor.dart: This package doesn't depend on meta.
  import 'package:meta/meta.dart' show required;
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Solution

Add explicit dependency on the meta package.

Testing

• CI passes
• pub publish --dry-run does not show the meta package warning

Code Review

@Workiva/web-platform-pp

[aviary-wf]

Raven

Number of Findings: 0

[codecov-io]

Codecov Report

Merging #284 into master will not change coverage.
The diff coverage is n/a.

[jayudey-wf]

+10

• verified that running pub publish --dry-run produced no warnings related to the meta package

[maxwellpeterson-wf]

QA +1

• Dependency update only
• Dev +1's
• CI passes
• Dependency scan clean

@Workiva/release-management-pp

[rmconsole-wf]

+1 from RM