Automatically label bug report issues with bug tag (#3288)

This change automatically sets the label on an issue
to `bug` if opened using the bug report template.

Signed-off-by: Eric Brown <eric_wade_brown@yahoo.com>

.github/ISSUE_TEMPLATE/bug_report.md

@@ -2,7 +2,7 @@
 name: Bug report
 about: Create a report to help us improve
 title: ''
-labels: ''
+labels: bug
 assignees: ''
 
 ---