Updates incorrect column types

[patcatgit]

A description of this PR, and why it is needed:

Changed population min and max column types to doubles, since non-ineger values are reported in certain articles. Changed asymptomatic_transmission reported to logical, consistent with database

Checklist:

• [ ] I have added new dependencies in DESCRIPTION
• [x] I have bumped the version number in DESCRIPTION
• [x] I have updated the NEWS.md
• [ ] I have added unit tests using testthat
• [x] I have checked that the package can install locally using devtools::install_local("<path-to-epireview>")
• [ ] I have added documentation where required
• [ ] My documentation includes examples of how to use the function
• [ ] If necessary, I have updated priority-pathogens

[sangeetabhatia03]

I have bumped up version number because of the other changes that had happened on develop before this was merged. Also resolved merge conflicts with develop.