Update bug-report.yml (#456)

Some issues are not related neither to iOS nor to Android platforms,
e.g. documentation. Current issue template forces users to choose either
iOS or Android. This change adds an option to the template that
indicates that issue affects both platforms or it's completely
independent of the platform.

## Description

<!-- Provide a concise and descriptive summary of the changes
implemented in this PR. -->

### Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] Documentation update (improves or adds clarity to existing
documentation)

### Tested on

- [ ] iOS
- [ ] Android

### Testing instructions

<!-- Provide step-by-step instructions on how to test your changes.
Include setup details if necessary. -->

### Screenshots

<!-- Add screenshots here, if applicable -->

### Related issues

<!-- Link related issues here using #issue-number -->

### Checklist

- [ ] I have performed a self-review of my code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have updated the documentation accordingly
- [ ] My changes generate no new warnings

### Additional notes

<!-- Include any additional information, assumptions, or context that
reviewers might need to understand this PR. -->

Author: msluszniak

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -77,6 +77,8 @@ body:
       options:
         - Android
         - iOS
+        - Both Android and iOS
+        - Platform agnostic
     validations:
       required: true