fixes wee little typo (#223)

Author: Jake Thomas

README.md

@@ -318,8 +318,7 @@ permissions to access the secrets being requested.
 
 ### Via google-github-actions/auth
 
-Use [google-github-actions/auth](https://github.com/google-github-actions/auth) to authenticate the action. You can use [Workload Identity Federation][wif] or traditional [Service Account Key JSON][sa] authentication.
-by specifying the `credentials` input. This Action supports both the recommended [Workload Identity Federation][wif] based authentication and the traditional [Service Account Key JSON][sa] based auth.
+Use [google-github-actions/auth](https://github.com/google-github-actions/auth) to authenticate the action. You can use [Workload Identity Federation][wif] or traditional [Service Account Key JSON][sa] authentication by specifying the `credentials` input. This Action supports both the recommended [Workload Identity Federation][wif] based authentication and the traditional [Service Account Key JSON][sa] based auth.
 
 See [usage](https://github.com/google-github-actions/auth#usage) for more details.