Fix appstream validation errors in metainfo file

[Hofer-Julian]

Description

• Add captions to all screenshots (required by Flathub linter)
• Only mark first screenshot as type="default"
• Wrap release description text in

  tags

These changes fix the following Flathub linter errors:

• appstream-screenshot-missing-caption
• description-spurious-text
• description-no-valid-content

Motivation and Context

The flathub-linter requires those changes

Types of changes

• 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 change)

Checklist:

• I have read the CONTRIBUTING guide.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

I provide my contribution under the terms of the license of this repository and I affirm the Developer Certificate of Origin.

[m3nu]

Thanks! Looking forward to how it looks like.

[Hofer-Julian]

Thanks! Looking forward to how it looks like.

Well not that much different 😅

Could you please make a new release?