Release 7.3.0

[github-actions[bot]]

Releasing 7.3.0.

Main changes in this release are adding a GITHUB_PAT so we don't run into the GitHub API rate limit, and updating workflows to avoid deprecations and warnings (Node, set-output, and save-state).

• https://github.com/cmu-delphi/forecast-eval/pull/296
• https://github.com/cmu-delphi/forecast-eval/pull/297
• https://github.com/cmu-delphi/forecast-eval/pull/295
• https://github.com/cmu-delphi/forecast-eval/pull/299
• https://github.com/cmu-delphi/forecast-eval/pull/301
• https://github.com/cmu-delphi/forecast-eval/pull/302