Fix issue template

Author: taoky

.github/issue_template.md .github/ISSUE_TEMPLATE/01-issue.md

@@ -0,0 +1,8 @@
+blank_issues_enabled: true
+contact_links:
+  - name: USTCLUG Mirror Request
+    url: https://github.com/ustclug/mirrorrequest/issues/new
+    about: 新增镜像请求 / New mirror request
+  - name: USTCLUG Discussions
+    url: https://github.com/ustclug/discussions/issues/new
+    about: 故障反馈、功能请求与其他讨论 / Bug report, feature request and discussion