Add issue template

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,23 @@
+<!--
+Thanks for using TinyGSM!
+
+Before opening an issue, please make sure you've read the README.
+We do not respond to general questions here, use gitter chat for that.
+Please provide the following information for all issues.
+The issues that do not contain the relevant information may be rejected.
+-->
+
+TinyGSM version: <!-- always try to use the latest -->
+Hardware: <!-- modem model, main board type, etc -->
+
+### Scenario, steps to reproduce
+<!-- What you are trying to achieve and you can't? -->
+
+### Expected result
+<!-- What are you expecting to happen as the consequence of above reproduction steps? -->
+
+### Actual result
+<!-- What actually happens after the reproduction steps? Include the error output or a link to a gist if possible. -->
+
+### AT command log
+<!-- The AT commands log you get using StreamDebugger or any other debugging method -->