Fetch a Push Credential
This operation fetches a single Push Notifications Credential using its ID.
Basic authentication of the form Basic <account_id:auth_token>.
Basic authentication of the form Basic <api_key:api_key_secret>.
Use this Credential as the default for the Push Notification App for the
given credentialType to send Push Notifications.
If a Credential of the given type doesn’t already exist,
this Credential automatically becomes the default.
The name of the app that this Credential is associated with.
This should be the same value as the appName set when registering devices for the app
with /PushNotifications/DeviceRegistrations