Update README.md (#52)

The single quotes with a variable substitution won't work. Set a
variable first before using it.

README.md

@@ -56,7 +56,8 @@ You can use `engflow_auth` to authenticate when no web browser is available, for
 1. At the beginning of a job, retrieve the secret and import it on stdin using the command below. The `-store=file` flag may be necessary to store the credential as an unencrypted file instead of your encrypted keyring. Non-interactive environments typically don't have an encrypted keyring.
 
     ```bash
-    engflow_auth import -store=file <<<'${ENGFLOW_CRED}'
+    ENGFLOW_CRED='<insert token info here>' 
+    engflow_auth import -store=file <<< "${ENGFLOW_CRED}"
     ```
    Replace `${ENGFLOW_CRED}` with the credential exported previously.