Clarify checkbox, add G6 to dropdown and remove G4, remove default wh…

…at happened

Signed-off-by: Aaron Liu <aaronliu0130@gmail.com>

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -12,7 +12,6 @@ body:
  label: What happened?
  description: Also tell us, what did you expect to happen?
  placeholder: Tell us what you see!
- value: "A bug happened!"
  validations:
  required: true
  - type: checkboxes
@@ -21,15 +20,15 @@ body:
  label: Reproducible?
  description: Is this issue reproducible on Firefox?
  options:
- - label: I have tested this on Firefox.
+ - label: I have checked that this issue cannot be reproduced on Mozilla Firefox.
  - type: dropdown
  id: version
  attributes:
  label: Version
  description: What version of our software are you running? Please DO NOT report Classic bugs.
  options:
+ - G6
  - G5
- - G4
  - Other
  validations:
  required: true