MAGETWO-54689: Update Issue Template for public GitHub

ISSUE_TEMPLATE.md

-Steps to reproduce
---
-1. Install Magento from `develop` branch.
-2. [Example] Add Configurable Product to the cart.
-3. ...
+<!--- Provide a general summary of the issue in the Title above -->
+<!--- Please check this article https://github.com/magento/magento2/wiki/Issue-reporting-guidelines before creating new issues -->
 
-Expected result
---
-1. [Example] Configurable product added to the shopping cart.
-2. ...
+### Preconditions
+<!--- Provide a more detailed information of environment you use -->
+<!--- Magento version, tag, HEAD, etc., PHP & MySQL version, etc.. -->
+1. 
+2. 
 
-Actual result
---
-1. [Example] Error message appears: "Cannot save quote".
-2. [Screenshot, logs]
-3. ...
+### Steps to reproduce
+<!--- Provide a link to an unambiguous set of steps to -->
+<!--- reproduce this bug include code to reproduce, if relevant -->
+1. 
+2. 
+3. 
+
+### Expected result
+<!--- Tell us what should happen -->
+1. 
+
+### Actual result
+<!--- Tell us what happens instead -->
+1. 
+
+<!--- (This may be platform independent comment) -->