Add integration test for Sphinx documentation build

[soaressgabriel]

Checklist

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Added tests for changed code.
• Updated documentation for changed code.

Description

• Add integration tests to ensure the documentation builds successfully without errors;
• Using GitHub Actions for CI to run these tests on each push and pull request will be added in Add validation rules for input rasters #111.

Related Issue

• Resolve Implement automated testing for RUBEM Sphinx documentation using pytest #135.

Motivation and context

• See Implement automated testing for RUBEM Sphinx documentation using pytest #135.

How has this been tested

• Manually.

Screenshots

• N/A

[LINAMARIAOSORIO]

LGTM