feat: update accounts:set to work with keychain managers

[k80bowman]

Summary

Updates the accounts:set command to work with keychain managers.

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:

1. Check out this branch and run npm i && npm run build
2. Run ./bin/run login to log in to your first account.
3. Run heroku accounts:add account1 to add this account to your accounts cache for .netrc
4. Logout of this account in the browser and then log in to a second account
5. Run ./bin/run login to log in to your second account
6. Run heroku accounts:add account2 to add this second account to your accounts cache for .netrc

Steps:

1. Run ./bin/run accounts:set <username for account 1>
2. Run ./bin/run apps and you should see the apps for account 1
3. Run ./bin/run accounts:set <username for account 2>
4. Run ./bin/run apps and you should see the apps for account 2
5. Run HEROKU_NETRC_WRITE=true ./bin/run accounts:set account1
6. Run HEROKU_NETRC_WRITE=true ./bin/run apps and you should see the apps for account 1
7. Run HEROKU_NETRC_WRITE=true ./bin/run accounts:set account2
8. Run HEROKU_NETRC_WRITE=true ./bin/run apps and you should see the apps for account 2

Screenshots (if applicable)

Related Issues

GUS work item: W-20867209