ci: fix publish_docs job fails with "permission denied"

[Musab1258]

Description

The publish_docs workflow pushes changes to this repository: "bitcoindevkit/bitcoindevkit.org" which requires valid credentials. By setting the persist-credentials to false in #1778, the credentials required are not made available.

Notes to the reviewers

To fix the issue I added a write permission to the publish_jobs, which will allow it to push changes without the credentials.

Changelog notice

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran cargo fmt and cargo clippy before committing

New Features:

• I've added tests for the new feature
• I've added docs for the new feature

Bugfixes:

• This pull request breaks the existing API
• I've added tests to reproduce the issue which are now passing
• I'm linking the issue being fixed by this PR

[notmandatory]

ACK 8b0b3a4

I agree with @ValuedMammal this is worth a try.

@Musab1258 If this doesn't fix the issue please create a new PR to roll it back. Thanks!

[notmandatory]

I think I have a working fix in #1896 which also reverts this PR.