Update and rename bug-report-for-adminlte-v3-x.md to bug-report-for-adminlte-v3.1-x.md (#3348)

.github/ISSUE_TEMPLATE/bug-report-for-adminlte-v3-x.md

@@ -2,7 +2,7 @@
 name: Bug report for AdminLTE v3.x
 about: Create a report to help us improve AdminLTE v3.x
 title: "[BUG]"
-labels: type:bug, version:3.x
+labels: type:bug, version:3.1.x
 assignees: ''
 
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