docs: update documents

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,35 +0,0 @@
----
-name: Bug report
-about: Create a report to help us improve
-title: ''
-labels: bug
-assignees: mob-sakai
-
----
-
-NOTE: Your issue may already be reported! Please search on the [issue tracker](../) before creating one.
-
-**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.
-
-**Environment (please complete the following information):**
- - Version [e.g. 1.0.0]
- - Platform: [e.g. Editor(Windows/Mac), Standalone(Windows/Mac), iOS, Android, WebGL]
- - Unity version: [e.g. 2018.2.8f1]
- - Build options: [e.g. IL2CPP, .Net 4.x, LWRP]
-
-**Additional context**
-Add any other context about the problem here.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,22 +0,0 @@
----
-name: Feature request
-about: Suggest an idea for this project
-title: ''
-labels: enhancement
-assignees: mob-sakai
-
----
-
-NOTE: Your issue may already be reported! Please search on the [issue tracker](../) before creating one.
-
-**Is your feature request related to a problem? Please describe.**
-A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
-
-**Describe the solution you'd like**
-A clear and concise description of what you want to happen.
-
-**Describe alternatives you've considered**
-A clear and concise description of any alternative solutions or features you've considered.
-
-**Additional context**
-Add any other context or screenshots about the feature request here.

.github/ISSUE_TEMPLATE/question.md

@@ -1,16 +0,0 @@
----
-name: Question
-about: Ask a question about this project
-title: ''
-labels: question
-assignees: mob-sakai
-
----
-
-NOTE: Your issue may already be reported! Please search on the [issue tracker](../) before creating one.
-
-**Describe what help do you need**
-A description of the question.
-
-**Additional context**
-Add any other context or screenshots about the question here.