Add Expo plugin with expo and eas CLI support

[CodeByZach]

Overview

Adds a shell plugin for Expo, supporting both the expo and eas CLIs. Authentication is handled via the EXPO_TOKEN environment variable using access tokens generated from the Expo dashboard.

Type of change

• Created a new plugin
• Improved an existing plugin
• Fixed a bug in an existing plugin
• Improved contributor utilities or experience

Related Issue(s)

• Resolves: #
• Relates: #

How To Test

1. Generate an access token at https://expo.dev/accounts/[account]/settings/access-tokens
2. Build the plugin locally: make expo/build
3. Initialize: op plugin init expo
4. Test authentication: expo whoami

Changelog

Authenticate the Expo and EAS CLIs using 1Password Shell Plugins.