feat: update accounts and accounts:current commands to use the credential manager

[k80bowman]

Summary

Updates the heroku accounts and heroku accounts:current commands so they are able to retrieve a user's accounts from their system keychain instead of relying on the cache file used when a user's token is stored in a .netrc file. The .netrc implementation remains the same.

Also fixes an issue with the git:credentials command that was causing the Windows test suites to timout and fail.

Type of Change

Breaking Changes (major semver update)

• Add a ! after your change type to denote a change that breaks current behavior

Feature Additions (minor semver update)

• feat: Introduces a new feature to the codebase

Patch Updates (patch semver update)

• fix: Bug fix
• deps: Dependency upgrade
• revert: Revert a previous commit
• chore: Change that does not affect production code
• refactor: Refactoring existing code without changing behavior
• test: Add/update/remove tests

Testing

Notes:

Setup:

1. Check out this branch and run npm i && npm run build
2. Login using ./bin/run login
3. Run HEROKU_NETRC_WRITE=true ./bin/run accounts:add to add your account to your .netrc accounts cache. Use the name arg to give it a recognizable name, like "personal" or "work".

Steps:

1. Run ./bin/run accounts. You should see one account in your list, labeled with your email address, with a star next to it. This comes from the keychain.
2. Run HEROKU_NETRC_WRITE=true ./bin/run accounts. You should see one account in your list, labeled with the recognizable name you chose above, with a star next to it. This comes from the .netrc accounts cache.
3. Run ./bin/run accounts:current. You should see your account email address. This comes from the keychain.
4. Run HEROKU_NETRC_WRITE=true ./bin/run accounts:current. You should see the recognizable name you gave your account above. This comes from the .netrc accounts cache.

Screenshots (if applicable)

Related Issues

GUS work item: W-20867059

[tlowrimore-heroku]

LGTM!