chore: remove nonsense placeholder for OS version

Author: claremacrae

.github/ISSUE_TEMPLATE/bug-report.yaml

@@ -88,7 +88,6 @@ body:
     attributes:
       label: Operating System Version(s)
       description: Which operating system version(s) are you using?
-      placeholder: 1.6.7
     validations:
       required: true