update issue template asking users to optionally provide an example source code while raising an issue (#778)

Author: sanagaraj-pivotal

.github/ISSUE_TEMPLATE/bug_report.md

@@ -32,9 +32,17 @@ If applicable, add screenshots to help explain your problem.
 **Stacktrace**
 If applicable, add the (sanitized) stacktrace here.
 
+**Example Source code to replicate the issue (Optional)**
+It would help us immensely if we were to have an example test source code or a snippet where you can see this problem, you could attach a zip file along with this issue. 
+
+Although this section is optional, it would speed up our process of providing a fix. 
+P.S. Please remove any sensitive data and do not upload any proprietary source.
+
 **Desktop (please complete the following information):**
  - OS: [e.g. Windows]
  - Version [e.g. 10]
 
+
 **Additional context**
 Add any other context about the problem here.
+