Update issue templates

Author: Hanjaemo

.github/ISSUE_TEMPLATE/bug_report.md

@@ -2,8 +2,8 @@
 name: Bug report
 about: Create a report to help us improve
 title: "[BUG]"
-labels: ''
-assignees: 
+labels: "\U0001F468\U0001F3FB‍\U0001F4BBbackend"
+assignees: ''
 
 ---
 

.github/ISSUE_TEMPLATE/feature_request.md

@@ -2,7 +2,7 @@
 name: Feature request
 about: Suggest an idea for this project
 title: "[FEAT]"
-labels: ''
+labels: "\U0001F468\U0001F3FB‍\U0001F4BBbackend"
 assignees: ''
 
 ---