Use covid data from OWID rather than {covidregionaldata}

[pratikunterwegs]

This issue is to request that the dependency on {covidregionaldata} data be swapped out in favour of Covid-19 data from Our World in Data, via the {owidR} package. {owidR} is on CRAN, removing one blocker dependency (see relevant discussion linked below).

Yep, could import from any alternative COVID data source that has cases and deaths over sufficiently long period to expect a change from accumulation of immunity (e.g. timeseries from OWID? https://ourworldindata.org/coronavirus). {covidregionaldata} was used as illustrative example in early versions of package, so not reason this has to be the go-to dependency.

Originally posted by @adamkucharski in epiverse-trace/epiverse-trace.github.io#85 (reply in thread)

[pratikunterwegs]

Fixed in PRs #58 and #55.