Log Message:
py-landslide: updated to 1.1.8

v1.1.8
- Explicitly support Python v3.8
- Test Python v3.7 and v3.8 with CI
- Fix sample slideshow link in `setup.py`

v1.1.7
- Change "PrinceXML" references to "Prince"
- Upgrade `Jinja2` from v2.10 to v2.10.1
- Support `markdown` v3.0+
- Fix Prince integration for PDF output
- Use HTTPS URLs in generated HTML code