Update bug_report.yml to ask for MWE

[valentinsulzer]

Description

Explicitly ask for a MWE in the bug reports.

[codecov]

Codecov Report

Merging #1975 (b9b7ac8) into develop (7d28451) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #1975   +/-   ##
========================================
  Coverage    99.32%   99.32%           
========================================
  Files          346      346           
  Lines        19078    19078           
========================================
  Hits         18950    18950           
  Misses         128      128           

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