add a comment to explain our smoke tests need the plugin to run onPostBuild

Author: aitchiss

netlify.toml

@@ -10,6 +10,8 @@ package = "./src/index.js"
 
 [plugins.inputs]
 output_path = "reports/lighthouse.html"
+
+# Note: Required for our Cypress smoke tests
 fail_deploy_on_score_thresholds = "true"
 
 [plugins.inputs.thresholds]