Use alpha tag in upgrade command

[HiDeoo]

Description (required)

This PR updates the upgrade command used in the v6 upgrade guide to currently use the alpha tag.

For the beta, we should also be able to update it to beta.

Related issues & labels (optional)

• Closes #
• Suggested label: 6.0

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Tracked Files

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en/guides/upgrade-to/v6.mdx	Localization changed, will be marked as complete.

Warnings reference

Icon	Description
🔄️	The source for this localization has been updated since the creation of this pull request, make sure all changes in the source have been applied.

[sarah11918]

Thank you!