Update bug report format

[tizianocitro]

I think the new template should be:

<!-- Issue must include at least one label from (bug, chore, docs, feature, refactoring) -->

### 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]
 - Version: [e.g. 22]

### Additional context
Add any other context about the problem here.

[tizianocitro]

This also solves #129 for bug reports.