Add composer.json file to repo

[binaryfire]

HI guys

Can you please add a composer.json file to the repo so we can pull this in via composer? Most developers manage larger / more complex WordPress projects with composer. This should do the trick:

{
"name": "oktadeveloper/okta-wordpress-sign-in-widget",
"type": "wordpress-plugin",
"description": "Okta sign-in widget for WordPress.",
"keywords": ["okta", "authentication", "login"],
"homepage": "https://github.com/oktadeveloper/okta-wordpress-sign-in-widget",
"license": "GPL-2.0+",
"support": {
"issues": "https://support.okta.com"
},
"require": {
"php": ">=5.3.0",
"composer/installers": "~1.0"
}
}

Also, could you add the following in the plugin's header so it works with the GitHub Updater plugin (https://github.com/afragen/github-updater):

GitHub Plugin URI: afragen/github-updater
GitHub Plugin URI: https://github.com/afragen/github-updater

Thanks!