chore: add issue template [ci skip]

Author: yyx990803

.github/issue-template.md

@@ -0,0 +1,16 @@
+<!--
+IMPORTANT: Please use the following link to create a new issue:
+
+  https://new-issue.vuejs.org/?repo=vuejs/vue-next
+
+If your issue was not created using the app above, it will be closed immediately.
+
+中文用户请注意：
+请使用上面的链接来创建新的 issue。如果不是用上述工具创建的 issue 会被自动关闭。
+-->
+
+<!--
+Love vuejs? Please consider supporting us via Patreon or OpenCollective:
+👉  https://www.patreon.com/evanyou
+👉  https://opencollective.com/vuejs/donate
+-->