misc: change gh issue types

.github/ISSUE_TEMPLATE/bug_report.md

----
-name: Bug report
-about: Create a report to help us improve Wiki.js
-title: ''
-labels: ''
-assignees: NGPixel
-
----
-
-**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.
-
-**Host Info (please complete the following information):**
- - OS: [e.g. Ubuntu 18.04, Docker]
- - Wiki.js version: [e.g. 2.0.1]
- - Database engine: [e.g. postgres 9.7, mysql 5.7]
-
-**Additional context**
-Add any other context about the problem here.