Use correct package name in license files

[joshwlambert]

The license files (LICENSE and LICENSE.md) were stating the copyright to the {readepi} authors. This PR updates the license files to specify the copyright holder is the {packagetemplate} authors.

I initially noticed this when updating a package that derived from {packagetemplate}. I had replaced all instances of "packagetemplate" but had missed these as I did not do a full package search of "readepi". This PR removes the last instances of "readepi" from {packagetemplate}.

[Bisaloo]

Can we use "the package authors" instead so that it kind of works even if not properly updated in packages using the template?

[joshwlambert]

We could add a point to the release_bullets() to remind maintainers to update the license in their package. However, this is only needed in the first release so I will not add it for now. If you think it should be included feel free to add before merging.

[Bisaloo]

Thanks! I have added it as a reminder in epiverse-trace/etdev#5 once we can move forward with this issue.