chore: update github docs

Author: jajugoguma

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,37 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: Bug
+assignees: ''
+---
+
+## Describe the bug
+A clear and concise description of what the bug is.
+
+## To Reproduce
+Steps to reproduce the behavior:
+1. Go to '...'
+2. Click on '....'
+3. Scroll down to '....'
+4. See error
+
+## Expected behavior
+A clear and concise description of what you expected to happen.
+
+## Screenshots
+If applicable, add screenshots to help explain your problem.
+
+## Desktop (please complete the following information):
+ - OS: [e.g. iOS]
+ - Browser [e.g. chrome, safari]
+ - Version [e.g. 22]
+
+## Smartphone (please complete the following information):
+ - Device: [e.g. iPhone6]
+ - OS: [e.g. iOS8.1]
+ - Browser [e.g. stock browser, safari]
+ - Version [e.g. 22]
+
+## Additional context
+Add any other context about the problem here.

.github/ISSUE_TEMPLATE/feature_request.md

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+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: Enhancement, Need Discussion
+assignees: ''
+---
+
+<!--
+Thank you for your contribution.
+
+When it comes to write an issue, please, use the template below.
+To use the template is mandatory for submit new issue and we won't reply the issue that without the template.
+-->
+
+## Version
+Write the version that you are currently using.
+
+## Development Environment
+Write the browser type, OS and so on.
+
+## Current Behavior
+Write a description of the current operation. You can add sample code, 'CodePen' or 'jsfiddle' links.
+
+```js
+// Write example code
+```
+
+## Expected Behavior
+Write a description of the future action.

.github/ISSUE_TEMPLATE/question.md

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+---
+name: Question
+about: Create a question about the Tree
+title: ''
+labels: Question
+assignees: ''
+---
+
+<!--
+  To make it easier for us to help you, please include as much useful information as possible.
+
+  Useful Links:
+  - tutorial: https://github.com/nhn/tui.tree/tree/master/docs
+  - API/Example: https://nhn.github.io/tui.tree/latest/
+
+  Before opening a new issue, please search existing issues https://github.com/nhn/tui.tree/issues
+-->
+
+## Summary
+
+A clear and concise description of what the question is.
+
+## Screenshots
+
+If applicable, add screenshots to help explain your question.
+
+## Version
+
+Write the version of the Editor you are currently using.
+
+## Additional context
+
+Add any other context about the problem here.