CI: Fix docs upload

[glensc]

Docs upload has been failing for a while:

Error: This request has been automatically failed because it uses a deprecated version of actions/upload-artifact: v3.
Learn more: https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/

• https://github.com/glensc/python-pytrakt/actions/runs/13068289939/job/36464362058

[glensc]

Enabled dependabot updates:

• 09b7c45

Refs

• https://github.com/glensc/python-pytrakt/settings/security_analysis

[glensc]

Fixed:

• https://github.com/glensc/python-pytrakt/actions/runs/13068483890