Add a timeout for update as well

this will send a notification if an update gets stuck

src/mailer.js

@@ -17,6 +17,7 @@ exports = module.exports = {
     backupFailed: backupFailed,
 
     certificateRenewalError: certificateRenewalError,
+    boxUpdateError: boxUpdateError,
 
     sendTestMail: sendTestMail,
 
@@ -411,6 +412,24 @@ function certificateRenewalError(mailTo, domain, message) {
     });
 }
 
+function boxUpdateError(mailTo, message) {
+    assert.strictEqual(typeof mailTo, 'string');
+    assert.strictEqual(typeof message, 'string');
+
+    getMailConfig(function (error, mailConfig) {
+        if (error) return debug('Error getting mail details:', error);
+
+        var mailOptions = {
+            from: mailConfig.notificationFrom,
+            to: mailTo,
+            subject: util.format('[%s] Cloudron update error', mailConfig.cloudronName),
+            text: render('box_update_error.ejs', { message: message, format: 'text' })
+        };
+
+        sendMail(mailOptions);
+    });
+}
+
 function oomEvent(mailTo, program, event) {
     assert.strictEqual(typeof mailTo, 'string');
     assert.strictEqual(typeof program, 'string');