do not run custom signing locally

Author: davegarthsimpson

Diff for: electron-app/scripts/windowsCustomSign.js

@@ -1,6 +1,10 @@
 const childProcess = require('child_process');
 
 exports.default = async function (configuration) {
+  if (!process.env.GITHUB_ACTIONS) {
+    return;
+  }
+
   const SIGNTOOL_PATH = process.env.SIGNTOOL_PATH;
   const INSTALLER_CERT_WINDOWS_CER = process.env.INSTALLER_CERT_WINDOWS_CER;
   const CERT_PASSWORD = process.env.WIN_CERT_PASSWORD;