👷 Fix `publish.yml` deprecation warnings: Node 12 GH actions + set-output

[ebouchut]

⚠️ Running the github action publish.yml generates the following deprecation warnings:

• Node.js 12 actions are deprecated

  Node.js 12 actions are deprecated. Please update the following actions to use Node.js 16: JamesIves/github-pages-deploy-action@v4.2.5. For more information see: https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/.

• The set-output command is deprecated and will be disabled soon

  The set-output command is deprecated and will be disabled soon. Please upgrade to using Environment Files. For more information see: https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

💚 The fix consists in upgrading 2 Github Actions and giving write access to the Github action script:

• Upgrade actions/setup-python Github Action to v4 from v3
• Upgrade JamesIves/github-pages-deploy-action Github Action to v4 latest from v4.2.5
  • Remove set-output command is deprecated See: https://github.com/JamesIves/github-pages-deploy-action/issues/1241
  • Remove Node.js 12 actions are deprecated
  • Add content write permission to publish.yml Github Action (read-only by default) See: https://github.com/JamesIves/github-pages-deploy-action/issues/1285

[ebouchut]

This fixed a https://github.com/LoopKit/looptips/security/dependabot/1