Gov-uk-dashboards

Adding a new methodology image.

What's Changed
* New image for Methodology by Jandums in https://github.com/communitiesuk/pkg_gov_uk_dashboards/pull/139


**Full Changelog**: https://github.com/communitiesuk/pkg_gov_uk_dashboards/compare/v9.20.0...v9.21.0

Update how to images for Oflog.

- Add new `context_banner()` component for adding context to aid interpretation of data

- Add ability to modify inline styling on warning message component.

Fix pandas warning in table code