Re-add issue template

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,13 @@
+Please check these things before submitting your issue:
+
+- [ ] Make sure you're using the latest version of PHPMailer
+- [ ] Check that your problem is not dealt with in [the troubleshooting guide](https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting), especially if you're having problems connecting to Gmail or GoDaddy
+- [ ] Include sufficient code to reproduce your problem
+- [ ] If you're having an SMTP issue, include the debug output generated with `SMTPDebug = 2` set
+- [ ] If you have a question about how to use PHPMailer (rather than reporting a bug in it), tag a question on Stack Overflow with `phpmailer`, but [**search first**](http://stackoverflow.com/questions/tagged/phpmailer)!
+
+# Problem description
+
+# Code to reproduce
+
+# Debug output