Retain names of versions when subsetting

[DavisVaughan]

Currently with dev usethis I see this with use_version() with no arguments

> usethis::use_version()
Current version is 0.5.2.9000.
What should the new version be? (0 to exit) 

1: major --> 1.0.0
2: minor --> 0.6.0
3: patch --> 0.5.3
4:   dev --> 0.5.2.9001

Selection: 2
✔ Setting Version field in DESCRIPTION to '0.6.0'
Error in if (names(new_ver) == "dev") { : argument is of length zero

This is due to this change in choose_version() #1784

Particularly, this line, which now uses [[ to subset versions (which is reasonable because there is only 1 choice).

usethis/R/version.R

Line 121 in a336c67

versions[[choice]]

It is problematic here because [[ drops the names of versions, and we actually need the name to be returned for use in use_version()

[DavisVaughan]

Failing until #1807 is merged

[jennybc]

Thanks!