gh: don't use code blocks in Bug report template

The Bug report template turns the textareas into code blocks. This
leads to some weird formatting. Remove the offending "render:" attribute.

Signed-off-by: Lorenz Bauer <lmb@isovalent.com>

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -14,15 +14,13 @@ body:
       description: |
         A clear and concise description of what the bug is.
         Include what you expected to happen instead.
-      render: markdown
     validations:
         required: true
 
   - type: textarea
     attributes:
       label: How to reproduce
       description: "Steps to reproduce the behavior."
-      render: shell
     validations:
         required: true