Update GCP's SA setup instructions
@@ -25,7 +25,7 @@ service account that has authorization to push to Google Container Registry:
4. Click **Create service account**
5. Give your account a descriptive name such as "binderhub-builder"
6. Click ``Role -> Storage -> Storage Admin`` menu option
-7. Check **Furnish new private key**
+7. Click **Create Key**
8. Leave key type as default of **JSON**
9. Click **Create**
