[skip changelog] Update broken or outdated references to docs workflow

[per1234]

Please check if the PR fulfills these requirements

• The PR has no duplicates (please search among the Pull Requests
  before creating one)
• The PR follows our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

• What kind of change does this PR introduce?

Bug fix.

• What is the current behavior?

The docs workflow was split into two workflows: publish-docs and validate-docs, but the references to the original workflow were not updated. This resulted in two problems:

• The "docs" badge in the readme won't reflect the true state of the documentation publishing system
• Broken link in CONTRIBUTING.md

• What is the new behavior?

All references to the docs workflow have been updated to point to the publish-docs workflow.

• Does this PR introduce a breaking change?

No