ci(workflows): minor changes

[younke]

Summary

• Update CI workflows to use master as the default branch instead of main
• Add weekly scheduled run (cron) to the build workflow
• Rename GITHUB_API_TOKEN to GITHUB_TOKEN in utils.bash for consistency with GitHub Actions conventions

Changes

CI Workflows

• build.yml: Changed trigger branch from main to master, added weekly scheduled cron job
• lint.yml: Changed trigger branch from main to master
• test-mise.yml: Added master branch trigger for push events, reordered triggers

Scripts

• lib/utils.bash: Renamed environment variable from GITHUB_API_TOKEN to GITHUB_TOKEN

Test Plan

• Verify workflows trigger correctly on push to master
• Verify workflows trigger correctly on pull requests
• Verify scheduled runs work as expected