fix(actions): added back fetch-depth: 0

[dreamorosi]

Description of your changes

This PR reintroduces a config item that was removed in #805 while trying to solve another tangential issue.

The setting in question is fetch-depth: 0 and its absence seems to cause the fail of the Action at a later point.

error: failed to push branch gh-pages to origin: "To https://github.com/awslabs/aws-lambda-powertools-typescript
[rejected]        gh-pages -> gh-pages (fetch first)
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details."
Error: Process completed with exit code 1.

Unfortunately I was not able to catch this error because the fork I was testing on didn't have GitHub Pages enabled, so it wouldn't fail at that point.

See #805 for full context.

How to verify this change

See on-merge-to-main execution results after merging.

Related issues, RFCs

#805

PR status

Is this ready for review?: YES
Is it a breaking change?: NO

Checklist

• My changes meet the tenets criteria
• I have performed a self-review of my own code
• My changes generate no new warnings
• The PR title follows the conventional commit semantics

Breaking change checklist

N/A

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