chore: rename repo Dragonfly2 to dragonfly

[gaius-qi]

Relevant Issue (if applicable)

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Details

Please describe the details of PullRequest.
This pull request includes a minor correction in the README.md file to update a link for the Dragonfly project.

• Updated the link for Dragonfly in the distribution section from dragonflyoss/Dragonfly2 to dragonflyoss/dragonfly to correct the reference.

Issue: dragonflyoss/dragonfly#3714

Types of changes

What types of changes does your PullRequest introduce? Put an x in all the boxes that apply:

• 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)
• Documentation Update (if none of the other choices apply)

Checklist

Go over all the following points, and put an x in all the boxes that apply.

• I have updated the documentation accordingly.
• I have added tests to cover my changes.